bluuebunny/crossref_metadata_2025 huggingface dataset:
True stabilization: A mechanism for the behavior of lead compounds and other primary stabilizers against PVC thermal dehydrochlorination
Authors: Michell E. W. J.
Published: December 2004

A free‐radical mechanism by which lead compounds are thought to inhibit thermal dehydrochlorination of polyvinyl chloride (PVC) is described. This mechanism is called “true stabilization” in order to distinguish it from simple hydrogen chloride (HCl) scavenging, which is a well‐known and sometimes important function of all primary stabilizers used in PVC. In true stabilization, it is thought that stearate or other aliphatic carboxylate groups (initially from lubricants) react with reservoirs of basic lead compound such as the carbonates, dibasic lead phosphite, the phthalates, or the sulfates, to give mobile carboxylates of lead. These latter salts then react with chlorine atoms released by the hot PVC, giving chlorides of lead and aliphatic carboxylate free‐radicals. Hence the chlorine atoms are trapped and unable to propagate free‐radical dehydrochlorination. Also it is thought that the aliphatic carboxylate free‐radicals esterify PVC molecules at methylenic carbon atoms (from which hydrogen atoms have been removed by chlorine atoms giving HCl and free‐radical sites in the polymer chain). Thus, unpaired electrons on the carboxylate free‐radicals and on these methylenic carbon atoms in the PVC molecules are paired, so that the neighboring chlorine atoms in polymer chloromethylenic groups are stabilized. Hence loss of chlorine atoms in the free‐radical dehydrochlorination of PVC is prevented. The pendant aliphatic carboxylate groups dissociate from the PVC molecules taking chloromethylenic hydrogen atoms to form acid molecules, and leaving chlorine atoms in relatively stable vinyl type groups. The aliphatic carboxylic acids react with more of the basic lead compound reservoir, giving mobile carboxylates of lead which can enter further reactions as just described. Thus, the true stabilizing mechanism is continuous and cyclic, while the reservoir of basic lead is available, and the PVC thermal dehydrochlorination will be retarded to almost negligible rates in favorable circumstances. It is thought that the behaviors of metal soaps and of organo‐tin stabilizers may be encompassed within the general true stabilization concepts of free‐radical exchanges and PVC esterifications described above. In these ways they also would retard PVC thermal dehydrochlorination. However, they are neutral compounds and have no basic reservoir which can react with carboxylic acids in the manner described above for lead stabilizers. Hence they are not able to confer long term stability on PVC in the way that basic lead stabilizing regimes do.
Role of organotin mercaptide stabilizer in heat and light stability of PVC
Authors: Rabinovitch Elvira B. , Dorsch John L. , Summers James W. , Quisenberry Joseph G.
Published: December 2004

Infrared analysis can be used to study the conversion of organotin mercaptide stabilizers in PVC from dialkyltin dimercaptide to dialkyltin monochloride monomercaptide to dialkyltin dichloride. This technique is used to study the effects of the stabilizer level and thermal heat history on the light stability of PVC.
Synthetic magnesium silicate: A single‐component/multi‐functional modifier
Authors: Varela Manuel A. , Driscoll Stephen Burke , Grolman Cory Peter , Mehta Naresh R.
Published: December 2004

Recent laboratory and in‐production tests have indicated the attractive commercial properties of synthetic magnesium silicate in plastics processing. In addition to its enhancing the flow behavior/materials handling of the base powdered resin, such as PVC, it has also proved to be a valuable, yet inexpensive polymer modifier. This non‐abrasive single‐component additive has demonstrated clearly its multi‐functional capabilities. For example, when compounded (at 0.5 to 1.5 phr) in a standard rigid vinyl formulation, the synthetic magnesium silicate contributed to improved compaction in the extruder feed section, initiated a faster fusion time, reduced melt viscosity, and enhanced thermal stability. Laboratory torque rheometer numbers and ASTM D 4440 Rheometrics Dynamic Spectrometer viscoelastic behavior is included along with typical extrusion and physical property test data. The significance of the co‐stabilization was complemented by the enhancement of physical properties, reduction of the necessary amount of lubricant, and did not affect sample color and appearance.
The effect of barium and cadmium stabilizers on the thermal dehydrochlorination of poly(vinyl chloride): A resonance Raman spectroscopic study
Authors: Gerrard D. L. , Bowley H. J. , Biggin I. S.
Published: December 2004

A laser Raman spectroscopic study has been made of the effect of barium and cadmium stabilizers on the thermal dehydrochlorination of poly(vinyl chloride) (PVC). The results obtained indicate that, in terms of the total level of dehydrochlorination, cadmium stearate is not as superior to barium stearate as the visual appearance of the polymer suggests. Also, the level of dehydrochlorination produced in the presence of a mixed stabilizer is not significantly lower than that produced in the presence of barium stearate alone, while samples of the latter exhibit much stronger color. It has also been shown that cadmium stearate can reduce the length of long polyene sequences, presumably by a reaction near the center of such a sequence.
The effect of fillers on the impact properties of oxytuf high impact PVC
Authors: Schwartz Willis T.
Published: December 2004

Oxytuf® mass polymerized PVC (IIP) contains grafted rubber moieties which provide for excellent impact resistance. The addition of a particulate filler to this resin with preservation of impact properties can be accomplished providing the particles are submicron and can be readily dispersed in the resin. Small particle size, surface treated, precipitated CaCO3, when added to IIP provided impact retention superior to that of a homopolymer control containing an added, non‐grafted impact modifier.
An examination of DSC as a method of characterization of PVC lubricants
Authors: Holsopple Peggy S.
Published: December 2004

Differential Scanning Calorimetry (DSC) has been used to characterize various lubricant additives for PVC in order to determine effectiveness. Depending on the processing period, and therefore the temperature profile, each lubricant undergoes a change in the internal vs. external nature of its behavior. In the process described, monitoring of the glass‐transition temperature produces evidence for the effectiveness of additives as internal lubricants.
Study of the preparation of plasticized PVC with a surface with barrier properties
Authors: Aboutaybi A. , Bouzon J. , Vergnaud J. M.
Published: December 2004

Plasticized PVC sheets are often used in packaging for blood or liquid foods, as well as cosmetics or solvents. Two matter transfers may take place: the liquid entering the PVC, and the plasticizer leaving the solid. These transfers are detrimental to the polymer, which becomes less flexible, and to the liquid, which is polluted. A two‐step process for preparing plasticized PVC samples with low matter transfers is studied. The polymer is immersed into a liquid for a short time and then dried. At the end of the process, a steep gradient of concentration is obtained next to the PVC surface both for the plasticizer and the liquid, with a low concentration on the surface. As the process of transport is controlled by diffusion with concentration‐dependent diffusivities, very low initial rate of transport is obtained for the final PVC. Models based on numerical methods with finite differences are used in order to describe the process and provide a fuller insight of its mechanism.
Heat distortion temperature modification of rigid PVC and chlorinated PVC: A method to produce low smoke compositions
Authors: Termine Enrico J.
Published: December 2004

The use of a new low smoke, heat distortion temperature modifier for rigid PVC and chlorinated PVC is discussed. This material, CN‐1427, is a tetrabromobisphenol A carbonate oligomer which is compatible with vinyl compositions. The carbonate oligomer can be compounded into PVC resin to improve heat distortion temperature of PVC and CPVC by 20–30°C. Unlike conventional HDT modifiers, brominated carbonate oligomers do not increase smoke evolution during flammability testing. Thus, using carbonate oligomer technology, it is possible to achieve low smoke, Class I (ASTM E‐84) and V‐O flammability (UL‐94) performance. Vinyl compositions, modified with the carbonate oligomer described in this work, can be utilized as an alternative to expensive engineering thermoplastics. This paper reports recent studies on the use of carbonate oligomers as heat distortion temperature modifiers for low smoke vinyl applications. Formulation information addressing flammability and physical property performance is presented in detail.
Characterizing the quality of PVC by melt flow testing
Authors: Pinette Roger G.
Published: December 2004

Traditionally, PVC compounds are identified by reference to bulk properties such as hardness, specific gravity, tensile, elongation. While these are useful and descriptive notations, they do not serve effectively to define compound quality. Melt flow is broadly used to great advantage in testing most commerical thermo‐plastics as described in ASTM D‐1238. These procedures utilize the dual advantages that a plastometer is a very expedient instrument to use in a given processing facility, and that a MF test is highly sensitive, capable of detecting relatively small differences in polymer structure and composition. However, PVC's are not considered within D‐1238 for several important reasons. The thermal and rheological instabilities of PVC create special considerations in testing as well as in processing. Furthermore, the polymer is always used in a highly varied compounding‐ingredient‐environment which further complicates the problem.
Filler tolerance of dispersion resins: An analysis of oil absorption and particle size effects
Authors: Harvey W. Wallace
Published: December 2004

Plastisol rheological characteristics are of prime importance to the formulator and processor. As the formulas become more complicated, interactions can occur between ingredients that have significant effects on rheology. This paper explores aspects of the resin‐CaCO3filler interaction. Experiments investigating some of the effects of resin‐filler interaction on rheological behavior have been performed. The experiments indicate that particle size distributions of the resin and filler, as they relate to packing efficiency, have a significant effect on rheological behavior, especially at high filler concentrations. The effects of particle packing vs. oil absorption are also investigated and discussed.
The use of statistical process control in batch processed PVC compounding. Part II
Authors: Brown David J.
Published: December 2004

This paper describes various SPC methods that can be used to promote quality improvement, resulting in increased productivity and lower costs. By concentrating on preventative systems rather than detective systems, the operation has increased productivity by 5.0% over a period of two years with relatively little capital investment. This has resulted in an additional capacity of 650,000 kg per year.
Examples of recycled vinyl products
Authors: Summers James W. , Mikofalvy Bela K. , Boo H. Khim , Krogstie James M. , Sell W. Alan , Rodriguez Juan C.
Published: December 2004

We describe examples in which we have demonstrated the feasibility of collection, separation, cleaning, and manufacture of several recycled products. We show that vinyl in municipal solid waste can be recycled into bottles, drainage pipe, and drainage pipe fittings with good appearance and properties. We also demonstrate the feasibility that vinyl wire and cable can be recycled into a variety of applications, including wire and cable traffic cones and drainage pipe with good appearance and properties.
Unusual properties of Plasmodium falciparum actin: new insights into microfilament dynamics of apicomplexan parasites
Authors: Schüler Herwig , Mueller Ann-Kristin , Matuschewski Kai
Published: December 2004

Plasmodium falciparum, the etiologic agent of malaria, is a facultative intracellular parasite of the phylum Apicomplexa. A limited turnover of microfilaments takes place beneath the parasite plasma membrane, but the cytoplasm of apicomplexans is virtually devoid of F‐actin. We produced Plasmodium actin in yeast. Purified recombinant Plasmodium actin polymerized inefficiently unless both gelsolin and phalloidin were added. The resulting actin polymers appeared fragmented in the fluorescence microscope. Plasmodium actin bound DNaseI about 200 times weaker than bovine non‐muscle actin. Our findings suggest that the unique properties of Plasmodium actin can explain some of the unusual features of apicomplexan parasite microfilaments.
The plant P1B‐type ATPase AtHMA4 transports Zn and Cd and plays a role in detoxification of transition metals supplied at elevated levels
Authors: Mills Rebecca F. , Francini Alessandra , Ferreira da Rocha Pedro S.C. , Baccarini Paul J. , Aylett Melissa , Krijger Gerard C. , Williams Lorraine E.
Published: December 2004

The transition metal Zn is essential for many physiological processes in plants, yet at elevated concentrations this, and the related non‐essential metal Cd, can be toxic. Arabidopsis thaliana HMA4, belonging to the Type P1B subfamily of P‐type ATPases, has recently been implicated in Zn nutrition, having a role in root to shoot Zn translocation. Using Arabidopsis insertional mutants, it is shown here that disruption of AtHMA4 function also results in increased sensitivity to elevated levels of Cd and Zn, suggesting that AtHMA4 serves an important role in metal detoxification at higher metal concentrations. AtHMA4 and a truncated form lacking the last 457 amino acids both confer Cd and Zn resistance to yeast but a mutant version of the full‐length AtHMA4 (AtHMA4‐C357G) does not; this demonstrates that the C‐terminal region is not essential for this function. Evidence is presented that AtHMA4 functions as an efflux pump.
Identification of proteins interacting with the RNAPII FCP1 phosphatase: FCP1 forms a complex with arginine methyltransferase PRMT5 and it is a substrate for PRMT5‐mediated methylation
Authors: Amente Stefano , Napolitano Giuliana , Licciardo Paolo , Monti Maria , Pucci Piero , Lania Luigi , Majello Barbara
Published: December 2004

FCP1, a phosphatase specific of the carboxyl‐terminal‐domain of the large subunit of the RNA polymerase II (RNAPII), stimulates transcription elongation and it is required for general transcription and cell viability. To identify novel interacting proteins of FCP1, we used a human cell line expressing an epitope flagged FCP1 and proteins, which formed complexes with FCP1, were identified by mass spectrometry. We identified four proteins: RPB2 subunit of the RNAPII, the nuclear kinase, NDR1, the methyltransferase PRMT5 and the enhancer of rudimentary homologue (ERH) proteins. Intriguingly, both the PRMT5 and ERH proteins are interacting partners of the SPT5 elongation factor. Interactions of RPB2, ERH, NDR1 and PRMT5 with FCP1 were confirmed by co‐immunoprecipitation or in vitro pull‐down assays. Interaction between PRMT5 and FCP1 was further confirmed by co‐immunoprecipitation of endogenous proteins. We found that FCP1 is a genuine substrate of PRMT5‐methylation both in vivo and in vitro, and FCP1‐associated PRMT5 can methylate histones H4 in vitro.
Comparison of the current RefSeq, Ensembl and EST databases for counting genes and gene discovery
Authors: Larsson Thomas P. , Murray Christian G. , Hill Tobias , Fredriksson Robert , Schiöth Helgi B.
Published: December 2004

Large amounts of refined sequence material in the form of predicted, curated and annotated genes and expressed sequences tags (ESTs) have recently been added to the NCBI databases. We matched the transcript‐sequences of RefSeq, Ensembl and dbEST in an attempt to provide an updated overview of how many unique human genes can be found. The results indicate that there are about 25 000 unique genes in the union of RefSeq and Ensembl with 12–18% and 8–13% of the genes in each set unique to the other set, respectively. About 20% of all genes had splice variants. There are a considerable number of ESTs (2 200 000) that do not match the identified genes and we used an in‐house pipeline to identify 22 novel genes from Genscan predictions that have considerable EST coverage. The study provides an insight into the current status of human gene catalogues and shows that considerable refinement of methods and datasets is needed to come to a conclusive gene count.
On the eigenvalues of the Chandrasekhar–Page angular equation
Authors: Batic Davide , Schmid Harald , Winklmeier Monika
Published: December 2004

In this paper we study for a given azimuthal quantum number κ the eigenvalues of the Chandrasekhar–Page angular equation with respect to the parameters μ≔am and ν≔aω, where a is the angular momentum per unit mass of a black hole, m is the rest mass of the Dirac particle and ω is the energy of the particle (as measured at infinity). For this purpose, a self-adjoint holomorphic operator family A(κ;μ,ν) associated to this eigenvalue problem is considered. At first we prove that for fixed κ∊R\(−12,12) the spectrum of A(κ;μ,ν) is discrete and that its eigenvalues depend analytically on (μ,ν)∊C2. Moreover, it will be shown that the eigenvalues satisfy a first order partial differential equation with respect to μ and ν, whose characteristic equations can be reduced to a Painlevé III equation. In addition, we derive a power series expansion for the eigenvalues in terms of ν−μ and ν+μ, and we give a recurrence relation for their coefficients. Further, it will be proved that for fixed (μ,ν)∊C2 the eigenvalues of A(κ;μ,ν) are the zeros of a holomorphic function Θ which is defined by a relatively simple limit formula. Finally, we discuss the problem if there exists a closed expression for the eigenvalues of the Chandrasekhar–Page angular equation.
Nonlinear dissipative eigenvalue problems with large initial conditions
Authors: Papanicolaou Vassilis G. , Newton Paul K.
Published: December 2004

We consider the initial value problem u″+ϕ(t)u′+B2u2p+1=0, t>0, u(0)=γ, u′(0)=0, where p is a positive integer, B, γ are positive parameters, and ϕ(t) is a positive function. The differential equation describes a (dissipative) oscillatory system whose amplitude A(t) decreases in time. For a given time b>0, our task is to compute the asymptotics of A(b), as γ→∞. In the case where ϕ∈C1(0,∞)∩L1(0,ε), we give an explicit answer. We also discuss the case where ϕ(t)=2∕t. This case is of particular interest since it is related to the nonlinear Schrödinger equation in three dimensions.
Dynamics of a gas bubble rising in an inclined channel at finite Reynolds number
Authors: Norman Catherine E. , Miksis Michael J.
Published: December 2004

The dynamics of a gas bubble rising in an inclined channel are investigated. The solution of this free boundary problem is determined numerically by using a level set method coupled with a finite difference solution of the Navier–Stokes equations. Results are presented as a function of Reynolds number, Bond number, and angle of inclination. Steady solutions for small values of both Reynolds and Bond number are found. In an inclined channel, we find that as these parameters are increased, the bubble will either periodically bounce off of the upper wall or rupture. In a vertical channel, with increasing Bond number, the bubble first begins to oscillate periodically, and then ruptures. In a vertical channel with increasing Reynolds number, the steady solution will bifurcate to a time periodic symmetric oscillation as the bubble rises up the channel, but further increase in Reynolds number allows for solutions that are no longer symmetric and oscillate back and forth between the channel walls. Our results parallel experimental work which shows that there is a critical angle of inclination at which the dynamics changes from bouncing bubbles to steady rising bubbles.
Radiobiological Basis for Cancer Therapy by Total or Half-Body Irradiation
Authors: Sakamoto Kiyohiko
Published: December 2004

The tumor control effects by total-body irradiation (TBI) or half-body irradiation (HBI) on tumor-bearing mice and human cancer were investigated. In fundamental studies using a murine experimental system, mice that received 10 or 15 cGy of TBI showed a high value of TD50 (number of tumor cells required for successful transplantation to a half group of injected sites) compared with nonirradiated control mice. The combination of low doses of TBI and local irradiation on tumor-bearing mice demonstrated enhanced tumor cell killing compared with only local irradiation, but this tumor-cell killing effect was not observed following 10 or 15 cGy of TBI alone. However, the suppression of distant metastasis of tumor cells was observed following low doses of TBI alone. Immunological studies on these effects suggested that TBI or HBI caused immunopotentiating effects. In clinical studies, malignant lymphoma (non-Hodgkin's lymphoma) was selected as the first disease for clinical trial. The results were promising for tumor control applications, except for advanced cases and very aged patients.
Alcohol: Friend or FOE? Alcoholic Beverage Hormesis for Cataract and Atherosclerosis is Related to Plasma Antioxidant Activity
Authors: Prickett Claire D. , Lister E. , Collins Michelle , Trevithick-Sutton C. C. , Hirst M. , Vinson J. A. , Noble E. , Trevithick J. R.
Published: December 2004

Objectives:

To correlate the oxidative state of postabsorptive blood plasma after consumption of one or three drinks of different beverages with known J-shaped epidemiological risk curves.

Design, interventions, and main outcome measures:

Red wine, lager beer, stout (alcoholic and alcohol-free), with antioxidant activity, and an aqueous solution of alcohol were compared for the plasma antioxidant or pro-oxidant activity in human volunteers following consumption of one or three typical drinks containing equivalent amounts of alcohol (except for an alcohol-free stout used as a control for stout).

Results:

One drink of red wine, lager beer, or stout (5% alcohol v/v, and alcohol-free) significantly increased the average antioxidant activity in plasma samples obtained from volunteers averaged over 240 min. Three drinks of red wine, lager beer, or stout (5% alcohol v/v, and alcohol-free) significantly increased the average pro-oxidant activity in plasma samples obtained from volunteers averaged over 360 min. For a solution of alcohol, three drinks resulted in pro-oxidant plasma on average, whereas while one drink did not significantly affect the plasma oxidative status. A preliminary experiment in which two volunteers showed a significantly increased time to metabolize ethanol after ingestion resulted in elevated antioxidant activity in plasma for lager beer and red wine.

Conclusions:

One drink of red wine, beer, or stout provided equivalent increases in plasma antioxidant activity. Three drinks of red wine, beer, or stout provided equivalent increases in plasma pro-oxidant activity. This may explain, at least in part, the decreased risk of cataract and atherosclerosis from daily consumption of one drink of different types of alcoholic beverages as well as the increased risk from daily consumption of three drinks of alcoholic beverages. The plasma pro-oxidant activity appears to be due to ethanol metabolism, whereas the antioxidant activity may be due to the absorption of polyphenols in the beverages.
POLYAMIC ALKYL ESTER SYSTEM AS AN ELECTRO-OPTIC POLYMER
Authors: PARK SEUNG KOO , DO JUNG YUN , JU JUNG JIN , PARK SUNTAK , KIM MIN-SU , LEE MYUNG-HYUN
Published: December 2004

A polyamic alkyl ester (PAE) was examined for the first time as a new candidate electro-optic (EO) polymer. An EO PAE was easily prepared from Disperse Red 1 (DR1) and a polyamic acid (PAA) synthesized from 2,2-bis(4-aminophenyl)hexafluoropropane and oxydiphthalic anhydride. The EO coefficient (r33) of the poled EO PAE film is around 25 pm/V at a wavelength of 1.55 μm when the film is poled with an applied voltage of 150 V/μm. The EO signal is thermostable. However, the chromophore is slightly released over 150°C.
ELECTRO-OPTIC AND ELECTRO-GYRATION EFFECTS IN CHIRAL MOLECULAR SYSTEMS
Authors: KIM AHYOUNG , WU J. W. , HAN S. H. , PARK BYOUNGCHOO , TAKEZOE HIDEO
Published: December 2004

The linear electro-optic (EO) and electro-gyration (EG) effects are studied in an optically active material systems including Bi 12 SiO 20 (BSO) oxide and bent-core liquid crystals. In an isotropic BSO sample, the breaking of intrinsic centro-symmetry allowed the EO modulation of the refractive index. In a mixture of bent-shaped liquid crystalline molecules having both optical activity and birefringence, the observed intensity modulation is investigated, which is related to the nonlinear optical responses of both the optical rotatory power and the birefringence. Both the linear EO and EG effects are understood in terms of the superposition principle of linear and circular birefringences.
NEW ACIDO- AND PHOTOSWITCHABLE CHROMOPHORES FOR SECOND-ORDER NONLINEAR OPTICS
Authors: SANGUINET L. , AHMED S. , POZZO J. L. , RODRIGUEZ V. , ADAMIETZ F.
Published: December 2004

New acidochromic and photochromic compounds with nonlinear optical properties have been designed and synthesized. The hyperpolarizabilities of the zwitterionic colored forms have been quantified with polarized hyper-Rayleigh scattering experiments. The static value of oxazolidino-indoline 2 is found to be as high as Disperse Red One. This opens the way to novel multi-addressable NLO-systems.
ENTROPY-ENTHALPY COMPENSATION BEHAVIOR REVISITED
Authors: KIRK WILLIAM R.
Published: December 2004

The origin of genuine (not statistically spurious) entropy-enthalpy compensation is investigated within standard liquid state statistical mechanics formalism. We treat two extreme cases of solvent-solute interaction: (1) those in which the changes "internal" to the solute dominate, and (2) those in which the solvent effect is dominant. They are evaluated in different ways, and lead to different predictions for compensation behavior. The first involves a conventional "thermodynamic perturbation" formalism.1,2 The second case leads to an Ornstein–Zernicke-like relationship that predicts predominantly entropically driven changes in free energy of reaction.
TWISTING: A QUANTITY DESCRIBING THE TOPOLOGICAL RELATION OF TWO PEPTIDE FRAGMENTS IN PROTEIN STRUCTURES
Authors: ZENG ZONG-HAO
Published: December 2004

A method for analyzing the topological relation of any two peptide fragments in a protein structure is given by making analogy of the two fragments with a braid. Knotted relations are analyzed by calculating polynomials for the two fragments separately and for the two as a whole, respectively. Twisting is calculated from the writhe number, which is a measure to the internal relative rotation during formation of the protein structure. Statistical analysis on the internal rotations of all known structures found that the relative rotation like a one-dimensional random walk with decreasing step lengths.
Ocular Melanogenesis: The Role of Antioxidants
Authors: Sarangarajan Rangaprasad , Apte Shireesh P.
Published: December 2004

Given the propensity of a large number of melanogenic pathways that can be modulated by cellular redox status, a causal role of the deficiency of ocular pigments such as melanin in the pathogenesis of age-related macular degeneration and evidence that melanin production does occur in the adult eye, it seems not improbable that antioxidants (or agents that modify cellular redox status) may have melanin stimulatory (or inhibitory) effects that are superimposible on their effects as mere free radical scavengers. More empirical studies are needed to investigate this phenomenon so that antioxidant therapy may prove more beneficial to patients with ocular degenerative diseases.
Immunohistochemical Localization of Angiotensin-Converting Enzyme, Angiotensin II and AT1 Receptor in Human Ocular Tissues
Authors: Savaskan Egemen , Löffler Karin U. , Meier Fides , Müller-Spahn Franz , Flammer Josef , Meyer Peter
Published: December 2004

We investigated the immunohistochemical distribution of 3 components of the renin-angiotensin system (RAS), angiotensin-converting enzyme (ACE), angiotensin II (AngII) and AT1 receptor (AT1), in the human eye. ACE and AngII were localized to nonpigmented epithelial cells of the ciliary body, to endothelial and epithelial cells of the cornea, to epithelial cells of the conjunctiva and to trabecular meshwork cells in the anterior part of the eye. In the posterior part of the eye, ACE and AngII were localized to ganglion cells, some cells in the inner nuclear layer, photoreceptor cells and to endothelial cells of the retinal and choroidal vessels. The overall intensity of AT1 immunoreactivity was weak in all ocular tissues, but the main localization was in ganglion cells. As a preliminary investigation, we were able to include 2 Alzheimer’s disease (AD) cases. In AD, no differences from controls were found in the cellular distribution and staining intensity of all 3 antigens. The manifold localization sites of the observed antigens point to rather generalized functions of the RAS in human ocular tissues, such as regulatory effects on neuronal cells, vessels and vitreous humor homeostasis.
Effects of Intravenous Administration of FR122047 (a Selective Cyclooxygenase 1 Inhibitor) and FR188582 (a Selective Cyclooxygenase 2 Inhibitor) on Prostaglandin-E2-Induced Aqueous Flare Elevation in Pigmented Rabbits
Authors: Abe Tomohiro , Hayasaka Yoriko , Zhang Xue-Yun , Hayasaka Seiji
Published: December 2004

Purpose: Two isoforms of cyclooxygenase (COX-1 and COX-2) exist. To determine in vivo effects of the intravenous administration of FR122047 (a selective COX-1 inhibitor), FR188582 (a selective COX-2 inhibitor), diclofenac sodium or dexamethasone phosphate disodium on prostaglandin-E2 (PGE2)-induced aqueous flare elevation and mRNA levels for COX-1 and COX-2 in pigmented rabbits. Methods: To produce aqueous flare elevation in rabbits, PGE2, 25 µg/ml, was applied to the cornea with the use of a glass cylinder. FR122047, FR188582, diclofenac sodium or dexamethasone phosphate disodium was intravenously injected before PGE2 application. Aqueous flare was measured with a laser flare-cell meter. The mRNA levels for COX-1 and COX-2 in the iris-ciliary body were determined by real-time polymerase chain reaction. Results: FR122047, FR188582 and diclofenac sodium (15 µmol/kg each) injected intravenously 30 min before PGE2 application inhibited 29 ± 5, 40 ± 12 and 50 ± 9% of aqueous flare elevation, respectively. Simultaneous injection of FR122047 (15 µmol/kg) and FR188582 (15 µmol/kg) 30 min before PGE2 application inhibited 61 ± 8% of flare elevation. Dexamethasone phosphate disodium (15 µmol/kg) injected intravenously 300 min before PGE2 application inhibited 68 ± 8% of aqueous flare elevation. Less than 3-fold changes in mRNA levels for COX-1 and COX-2 in the iris-ciliary body were noted after PGE2, FR122047, FR188582, diclofenac sodium or dexamethasone phosphate disodium treatment. Conclusion: It is possible that enzyme activities of both COX-1 and COX-2 may be involved in the mechanism of PGE2-induced aqueous flare elevation in pigmented rabbits.
The Periarterial Space in the Lung: Its Important Role in Lung Edema, Transplantation, and Microbial or Allergic Inflammation
Authors: Pabst R.
Published: December 2004

In mammal lungs different compartments for leukocytes can be identified during health and disease, e.g. lung interstitium, bronchoalveolar space, the epithelium and lamina propria of the air-conducting part. A so far neglected compartment is the space around the branches of the pulmonary arteries, characterized by a unique architecture of capillaries running in parallel to the pulmonary artery. This compartment – the periarterial space – is described and its phyiological and pathophysiological role reviewed. The periarterial space is infiltrated by different leukocyte subsets during edema formation in the early stages of a lung transplant rejection and, in particular, during inflammatory and allergic reactions. The periarterial compartment seems to be of major relevance in all these situations.
Evaluation of Expression of Apoptosis-Related Proteins and Their Correlation with HPV, Telomerase Activity, and Apoptotic Index in Cervical Cancer
Authors: Singh A. , Sharma H. , Salhan S. , Datta Gupta S. , Bhatla N. , Jain S.K. , Singh N.
Published: December 2004

Objective: The aim of this study was to examine the expression of apoptosis-related proteins in cervical cancer, and investigate their correlation with the apoptotic index (AI), telomerase activity, human papilloma virus (HPV) infection and clinicopathological characteristics. Methods: Fifty cervical cancer samples and 20 normal cervical tissues were assessed for the protein expression of survivin, Bcl-2, Cox-2, p53 and p73 by immunohistochemistry. HPV DNA was detected by PCR, telomerase activity by PCR-ELISA, and AI by TUNEL assay. Results: 46/50 cervical tumors (92%) showed an increased telomerase activity as compared to 3/20 (15%) controls. 45/50 (90%) cervical tumors were positive for HPV, of which 30 were HPV-16 positive and 5 were HPV-18 positive. 24/50 (48%) tumors were positive for survivin, 14 (28%) for Bcl-2, 13 (26%) for Cox-2, 19/45 (42%) for p73, 10/45 (24%) for p53. Telomerase activity was highest in tumors with the poorest grade. A positive correlation was seen between survivin and Bcl-2, survivin and tumor stage, Bcl-2 and Cox-2, p73 and p53 and p73 and the AI. Despite the overexpression of various antiapoptotic proteins, no significant difference was observed in the AI between tumors and controls. Conclusions: Since deregulation of the apoptotic pathway appears to occur in cervical cancer, some apoptosis-related proteins could be assessed as potential markers for progression/prognosis in cervical cancer. Additionally, newer proteins such as p73 may play a compensatory role for the nonfunctional proteins such as p53.
Menstrual Cycle-Dependent Changes in Visual Field Analysis of Healthy Women
Authors: Akar Yusuf , Yucel Iclal , Akar Munire Erman , Taskin Omur , Özer Hilmi O.
Published: December 2004

Purpose: To determine the effect of menstrual cycle phases on the visual field analysis of healthy females. Material and Methods: One randomly selected eye each of 59 healthy normally menstruating women, and of 54 men with no systemic and ocular problems, other than refractive error, were included in the study. Subjects underwent complete ocular examination, and standard achromatic perimetric (SAP) and short-wavelength automated perimetric (SWAP) analysis in both follicular (7th to 10th day of the cycle) and luteal phases (days 3–7 before the menstrual bleeding) of the menstrual cycle. Visual field analysis was performed using a Model 750 Humphrey Field Analyzer II (Humphrey Instruments Inc., San Leandro, Calif., USA) with full-threshold, central 30-2 program. Visual fields were divided into four regions as superior temporal, inferior temporal, superior nasal and inferior nasal, respectively. Results: The mean age of female (n = 59) and the male subjects (n = 54) were 34.6 ± 2.9 and 35.0 ± 2.7 years, respectively (p = 0.49). SWAP tests demonstrated a significantly decreased mean MS value in the luteal phase (p < 0.05). However, it did not change significantly with SAP tests. Regional MS values of both SAP and SWAP tests were not different in both phases of the menstrual cycle (all p values >0.05). Mean perimetric test durations obtained with both SAP and SWAP were not different throughout the menstrual cycle (both p values >0.05). Conclusion: Clinicians should verify menstrual status when evaluating a suspected loss of visual field sensitivity in menstruating women. The findings of the present study suggest that the SWAP test may be more sensitive to determine subtle sex hormone-dependent changes in visual field analysis of healthy women.
Ophthalmic Manifestations of Multiple Myeloma
Authors: Fung Shirley , Selva Dinesh , Leibovitch Igal , Hsuan James , Crompton John
Published: December 2004

Purpose: To describe ophthalmic manifestations in a series of patients with multiple myeloma (MM) and review the literature. Design: Retrospective case series. Methods: Review of all cases with ophthalmic manifestations of MM seen at the Department of Ophthalmology, Royal Adelaide Hospital, between 1987 and 2002. Results: Of all patients with MM who were managed at the Royal Adelaide Hospital in the study period, only 8 were referred to the Ophthalmology Department with ophthalmic manifestations. Five males and 3 females with a mean age of 61.25 years (range 42–78) who exhibited ophthalmic manifestations were studied. Six patients (75%) had known MM at the time of their ophthalmic evaluation. Four patients (50%) had neuro-ophthalmic symptoms resulting in diplopia or visual disturbances. Three patients (37.5%) presented with orbital involvement and 1 (12.5%) with hyperviscosity retinopathy. Five patients (62.5%) died within 2 months of their ophthalmic presentation. Conclusion: Ophthalmic manifestations of MM are uncommon and diverse. They may appear at the initial presentation of the disease or occur late in the disease process. Awareness of the possible manifestations may lead to an earlier diagnosis and have a positive influence on the disease course.
Vascular Access Monitoring: Methods and Procedures – Something to Standardize?
Authors: Lopot František , Nejedlý Bohdan , Válek Martin
Published: December 2004

The article discusses the issue of suitable parameters (pressures, recirculation and access flow) to assess hemodialysis vascular access quality (VAQ), available methods to measure those parameters and the setup of the entire VAQ surveillance system (VAQS) in a dialysis facility. Special attention is paid to factors which need some standardization to enable evaluation of VAQ trends in an individual as well as comparison of data from different patients and different dialysis facilities. The discussed procedures are documented with the authors’ own measurement results and the results of the VAQS implemented in their unit. Both dynamic and static pressures exhibit insufficient sensitivity in detecting stenoses in native arteriovenous fistulas. Access recirculation is a late finding because with its non-zero value dialysis quality is already compromised. Timely and reliable detection of a deteriorating access condition is enabled by access flow (QVA) only. No standardization is needed in extracorporeal blood flow used in QVA evaluation by ultrasonic dilution. Multiple measurements may increase the reliability of thermodilutional measurements and are a must in optodilutional ones. Timing of the measurement during dialysis should be standardized. Measurement frequency should take into account access type, QVA value and access history. Shortened intervals are needed in the immediate post-intervention period with regard to risk of re-stenosis incidence and strongly nonlinear QVA decreases in such cases. A significant shift-over from surgical interventions to balloon angioplasties is to be expected with the introduction of a VAQS, and appropriate measures must be taken to ensure their quick availability.
Efficacy of Cognitive Behaviour Therapy in Generalized Anxiety Disorders
Authors: Linden M. , Zubraegel D. , Baer T. , Franke U. , Schlattmann P.
Published: December 2004

Background: Generalized anxiety disorders (GAD) are amongst the most prevalent mental disorders. Recent studies have suggested that cognitive behaviour therapy (CBT) is an effective treatment for GAD. A controlled clinical trial was done to evaluate the efficacy of CBT treatment in outpatients with pure GAD who were treated by a therapist working in routine care. Methods: Seventy-two outpatients, fulfilling GAD criteria according to DSM-IV, were included in the study. From this group, 36 patients (CBT-A) were randomly assigned to 25 sessions of CBT and the other 36 formed a contact control group (CCG). After the contact control period (CC period), these patients were also treated with CBT (CBT-B), allowing not only a parallel group comparison but also an A-B comparison. Therapists were licensed full-time psychologists who worked routinely in outpatient care and had a professional training in CBT. Treatment was done in accordance with a manual, and treatment conformity was controlled by several methods. Results: The reduction in the score on the Hamilton Anxiety Observer Rating Scale was 6.4% (1.5 points) in the CCG, 35.4% (9.5 points) in the CBT-A and 47.3% (10.3 points) in the CBT-B. In the self-rating Spielberger State-Trait Anxiety Inventory, a reduction of 2.7% was seen in CCG, 14.6% in CBT-A, and 11.6% in CBT-B. According to the Clinical Global Impression Rating, 65.6% of patients were still at least moderately ill at the end of the CC period, while this rate was 33.4% at the end of CBT-A, or 15.7% at the end of CBT-B. All these differences between treatment and control group are statistically highly significant. The clinical improvement remained stable over a follow-up period of 8 months. Conclusions: CBT is an effective method of treatment for GAD. Differences between control and treatment group are comparable to or larger than those reported in studies on antidepressant drugs.
The Comparison of Topical Ibopamine 2% with Tonography to Identify the Outflow Resistance in Eyes with Ocular Hypertension
Authors: Hepsen Ibrahim F. , Yilmaz Harun , Keskin Ugur Can
Published: December 2004

Background: To evaluate the ability of topical ibopamine 2% to detect outflow resistance by comparing it with the tonography test in eyes with ocular hypertension (OHT). Methods: 62 eyes with OHT and 33 control eyes were included in this prospective study. Tonography was done manually as a standard outflow facility measurement. We used a C value of 0.18 µl/min/mm Hg or less and a Po/C value of 100 and above as a positive tonographic test. The ibopamine test performed on the following day was considered positive if there was an intraocular pressure (IOP) change of at least 3 mm Hg. Results: The sensitivity of the tonography and ibopamine tests was 69 and 53%, respectively, in eyes with OHT. The specificity of both tests was 97%. Although the sensitivity of the tonography test is higher than that of the ibopamine test, the difference between both was not statistically significant in these eyes (p = 0.409). Positive results in tonography were associated with higher IOP, while the results were not dependent on the IOP in the ibopamine test. Both tests together were positive in 33.87% (21 eyes) and negative in 11.29% (7 eyes) in 62 eyes with OHT. Conclusion: This study revealed that the ibopamine provocation test can detect outflow system resistance in eyes with OHT comparable with tonography which is a traditional outflow facility measurement. Ibopamine, however, can detect the eye with outflow impairment by a different and IOP-independent way, while tonography depends on IOP.
Medial Temporal Lobe Atrophy and APOE Genotype Do Not Predict Cognitive Improvement upon Treatment with Rivastigmine in Alzheimer’s Disease Patients
Authors: Visser Pieter Jelle , Scheltens Philip , Pelgrim Esther , Verhey Frans R.J.
Published: December 2004

Background: Only a subgroup of subjects with probable AD shows cognitive improvement after treatment with cholinesterase inhibitors. Objectives: To investigate whether atrophy of the medial temporal lobe and the apolipoprotein E (APOE) genotype could predict cognitive improvement in subjects with probable AD treated with rivastigmine. Methods: 121 subjects with mild to moderate probable AD were treated for 26 weeks with escalating doses of rivastigmine. Outcome measures were change on the MMSE and the ADAS-Cog between baseline and follow-up and treatment response defined as at least 2 points improvement on the MMSE or at least 4 points improvement on the ADAS-Cog. The study was an open-label multi-centre study in the Netherlands. Results: Subjects with medial temporal lobe atrophy (MTLA) tended to show more decline on the MMSE after correction for age, sex, education, baseline cognitive score, and dosage at week 26 compared with subjects without MTLA (p = 0.08). A significant interaction between MTLA and dosage at week 26 existed for change on the MMSE and ADAS-Cog: subjects with MTLA showed more cognitive decline than subjects without MTLA only in the group of patients who received a low dosage at week 26. MTLA was not associated with treatment response. The APOE genotype was not associated with change on the MMSE or ADAS-Cog or with treatment response. Conclusions: MTLA and the APOE genotype are not clinically useful predictors of cognitive response in subjects with probable AD who are treated with rivastigmine.
Chondrogenesis Mediated by PP
i
Depletion Promotes Spontaneous Aortic Calcification in NPP1−/− Mice
Authors: Johnson Kristen , Polewski Monika , van Etten Deborah , Terkeltaub Robert
Published: December 2004

Objective—

We recently linked human arterial media calcification of infancy to heritable PC-1/nucleotide pyrophosphatase phosphodiesterase 1 (NPP1) deficiency. NPP1 hydrolyzes ATP to generate PP
i
, a physicochemical inhibitor of hydroxyapatite crystal growth. But pathologic calcification in NPP1 deficiency states is tissue-restricted and in perispinal ligaments is endochondral differentiation–mediated rather than simply a dystrophic process. Because ectopic chondro-osseous differentiation promotes artery calcification in atherosclerosis and other disorders, we tested the hypothesis that NPP1 and PP
i
deficiencies regulate cell phenotype plasticity to promote artery calcification.

Methods and Results—

Using cultured multipotential NPP1−/− mouse bone marrow stromal cells, we demonstrated spontaneous chondrogenesis inhibitable by treatment with exogenous PP
i
. We also demonstrated cartilage-specific gene expression, upregulated alkaline phosphatase, decreased expression of the physiological calcification inhibitor osteopontin, and increased calcification in NPP1−/− aortic smooth muscle cells (SMCs). Similar changes were demonstrated in aortic SMCs from
ank/ank
mice, which are extracellular PP
i
–depleted because of defective ANK transmembrane PP
i
transport activity. Moreover, NPP1−/− and
ank/ank
mice demonstrated aortic media calcification by von Kossa staining, and intra-aortic cartilage-specific collagen gene expression was demonstrated in situ in NPP1−/− mice.

Conclusions—

NPP1 and PP
i
deficiencies modulate phenotype plasticity in artery SMCs and chondrogenesis in mesenchymal precursors, thereby stimulating artery calcification by modulating cell differentiation.