bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of human respiratory syncytial virus sequences in peripheral blood mononuclear cells
Authors: Yui Ikuko , Hoshi Akiyoshi , Shigeta Yukiko , Takami Takeshi , Nakayama Tetsuo
Published: May 2003

Peripheral blood mononuclear cells (PBMC) obtained from patients with lower respiratory infections were examined for the detection of human respiratory syncytial virus (RSV) sequences in the N region using the reverse transcription polymerase chain reaction (RT‐PCR). RSV infection was confirmed by at least one method, i.e., virus isolation, enzyme immunoassay for viral antigen, and RT‐PCR of nasopharyngeal secretions (NPS) samples. The detection rate for RSV RNA in PBMC obtained from RSV‐infected patients was 40% (38/94), compared to 5% (1/20) in controls (P = 0.002). Between the groups positive (38) and negative (56) for RSV RNA in PBMC, there was no significant difference in clinical parameters. Seven patients had eight episodes of reinfection and RSV RNA was detected in 50% (4/8) during consecutive infections. Sequences of their PBMC samples were distinct from those of prototype strains of subgroup A and B. However, they were not always consistent with those of paired NPS samples. The findings suggested that RSV RNA could be detected in PBMC even during reinfection and as might have the possibility of quasispecies dynamics, reflecting the nature of RNA viruses. J. Med. Virol. 70:481–489, 2003. © 2003 Wiley‐Liss, Inc.
Studies of neutralising antibodies to SV40 in human sera
Authors: Minor P. , Pipkin P. , Jarzebek Z. , Knowles W.
Published: May 2003

It has been suggested that the low levels of antibody to the simian polyoma virus SV40 found in human sera may be linked to the use of polio vaccines. Panels of sera from areas of the world with different vaccination histories were examined to see if consistent differences could be identified. In a total of 2,054 sera from the United Kingdom, 692 from Africa and 923 from Poland taken between 1985 and 1997, the seroprevalence was generally between 3 and 5%, although exceptionally one collection from Morocco had a prevalence of 100%, and one from Poland of 0.4%. The seroprevalence showed no obvious age‐dependent increase and titres were low compared to post infection animal sera. The results are consistent with previous studies and reveal no general geographically based differences related to possible differences in vaccination history, but the origin of the SV40 antibody in human sera remains to be established. J. Med. Virol. 70:490–495, 2003. © 2003 Wiley‐Liss, Inc.
Clinicopathological characteristics of superficial spreading type early gastric cancer
Authors: Imai Masato , Kondo Yukifumi , Osawa Shohei , Nishida Yasunori , Okada Kuniaki , Ishizu Hiroyuki , Masuko Hiroyuki , Hata Tsunetake , Uemura Kazuhito , Kina Masaya , Honda Shohei , Ishiyama Gentaro , Takahashi Toru , Hino Atsushi
Published: May 2003

Background and Objectives

Superficial spreading type early gastric cancer is characterized by its atypical growth pattern and occasionally indistinct tumor margin. Because it is a rare form of early gastric cancer, the clinicopathological details are not apparent. The aim of this study was to clarify the clinicopathological features of the superficial spreading type of early gastric cancer.

Methods

A retrospective study was conducted in 1,062 surgically resected patients with early gastric cancer. Hospital records were compared between patients with superficial spreading type early gastric cancer and those with more common types of early gastric cancer.

Results

Sixty‐nine patients (6.9%) had superficial spreading lesions. The male to female ratio was 1.2:1. The most frequent histological type was signet‐ring cell carcinoma (32%). The distinguishing histopathological features were submucosal invasion (67%), lymphatic invasion (32%), and lymph node metastasis (30%). There were discrepancies in tumor area between surgical findings and pathological diagnosis in 24 patients (35%) with superficial spreading type. More extensive lymph node dissection was performed and all patients survived in the group with superficial spreading lesions.

Conclusions

The most appropriate treatment for the superficial spreading type of early gastric cancer is wide surgical resection with extensive lymph node dissection. J. Surg. Oncol. 2003;83:94–98. © 2003 Wiley‐Liss, Inc.
Apolipoprotein D expression in cutaneous malignant melanoma
Authors: Miranda Eva , Vizoso Francisco , Martín Arancha , Quintela Isabel , Corte María Daniela , Seguí María Eugenia , Ordiz Iratxe , Merino Antonio Martínez
Published: May 2003

Background and Objectives

Apolipoprotein D (Apo D) is a protein component of the human plasma lipid transport system, and an androgen‐regulated protein in both breast and prostate cancer cell lines. Our goal was to evaluate the expression of Apo D in malignant cutaneous melanomas, as well as to assess its possible relationship to clinical and pathological parameters.

Methods

Apo D expression was analyzed in 32 paraffin‐embedded tissues from patients with invasive cutaneous malignant melanomas, in 8 samples from in situ melanoma, and in 10 samples from 10 benign lesions (4 dermal melanocytic nevi, 4 compound melanocytic nevi, and 2 dysplastic melanocytic nevi), using immunohistochemical techniques.

Results

The benign lesions were consistently negative for Apo D, whereas 3 of the 8 “in situ” melanomas (37.5%) and 12 of the 32 invasive melanomas (37.5%) showed positive immunostaining for Apo D. The percentage of Apo D‐positive tumors was significantly higher in nodular than in superficial spreading melanomas (P = 0.011) and in melanomas with vertical growth phase than in melanomas with radial growth phase (P = 0.02). In addition, the percentage of Apo D‐positive tumors was positively and significantly correlated with Clark's level of invasion (P = 0.046).

Conclusions

Apo D may be a new prognostic factor of unfavorable evolution in cutaneous malignant melanoma. J. Surg. Oncol. 2003;83:99–105. © 2003 Wiley‐Liss, Inc.
Kinetic study of the gas‐phase reaction of the nitrate radical with methyl‐substituted thiophenes
Authors: Cabañas B. , Martín P. , Salgado S. , Baeza M. T. , Albaladejo J. , Martínez E.
Published: May 2003

The gas‐phase reactions of the NO3 radical with 2‐methylthiophene, 3‐methylthiophene, and 2,5‐dimethylthiophene have been studied, using relative and absolute methods at 298 K. Determination of relative rate was performed using Teflon collapsible bag as the reaction chamber and gas chromatography as the analytical tool. For the absolute method, experiments were carried out using fast‐flow‐discharge technique with detection of NO3 by laser‐induced fluorescence. The temperature dependence was studied by the absolute technique for the reactions of NO3 with 2‐methylthiophene and 3‐methylthiophene in the range 263–335 K.

The proposed Arrhenius expressions for the reaction of the nitrate radical with 2‐methylthiophene and 3‐methylthiophene are k = (4 ± 2) × 10−16 exp[−(2200 ± 100)/T]] cm3 molecule−1 s−1 and k = (3 ± 2) × 10−15 exp[−(1700 ± 200)/T]] cm3 molecule−1 s−1, respectively. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 286–293, 2003
Experimental and modeling study of the oxidation of cyclohexene
Authors: Dayma G. , Glaude P. A. , Fournet R. , Battin‐Leclerc F.
Published: May 2003

Ignition delays of cyclohexene–oxygen–argon mixtures were measured behind shock. Mixtures contained 1 or 2% of hydrocarbons for equivalence ratios ranging from 0.5 to 2. Reflected shock waves permitted to obtain temperatures from 1050 to 1520 K and pressures from 7.7 to 9.1 atm. The experimental results exhibit an Arrhenius variation vs. temperature.

A detailed mechanism of the combustion of cyclohexene has been written in the line of the mechanism developed previously for the reaction of C3C4 unsaturated hydrocarbons (propyne, allene, 1,3‐butadiene, butynes); it is based on recent kinetic data values published in the literature and is consistent with thermochemistry. This mechanism has been validated by comparing the results of the simulations to the experimental results obtained for ignition delays. The main reaction pathways have been derived from flow rate and sensitivity analyses for the different temperature areas studied. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 273–285, 2003
Uncatalyzed and ruthenium(III)‐catalyzed reaction of acidic chlorite with methylene violet
Authors: Jonnalagadda S. B. , Shezi M. , Pare B.
Published: May 2003

The kinetics and mechanism of the uncatalyzed and Ru(III)‐catalyzed oxidation of methylene violet (3‐amino‐7‐diethylamino‐5‐phenyl phenazinium chloride) (MV+) by acidic chlorite is reported. With excess concentrations of other reactants, both uncatalyzed and catalyzed reactions had pseudo‐first‐order kinetics with respect to MV+. The uncatalyzed reaction had first‐order dependence on chlorite and H+ concentrations, but the catalyzed reaction had first‐order dependence on both chlorite and catalyst, and a fractional order with respect to [H+]. The rate coefficient of the uncatalyzed reaction is (5.72 ± 0.19) M−2 s−1, while the catalytic constant for the catalyzed reaction is (22.4 ± 0.3) × 103 M−1 s−1. The basic stoichiometric equation is as follows: 2MV+ + 7ClO2− + 2H+ = 2P + CH3COOH + 4ClO2 + 3Cl−, where P+ = 3‐amino‐7‐ethylamino‐5‐phenyl phenazinium‐10‐N‐oxide. Stoichiometry is dependent on the initial concentration of chlorite present. Consistent with the experimental results, pertinent mechanisms are proposed. The proposed 15‐step mechanism is simulated using literature; experimental and estimated rate coefficients and the simulated plots agreed well with the experimental curves. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 294–303, 2003
Rate coefficient for the reaction of CCl3 radicals with ozone
Authors: Imamura Takashi , Chono Hideharu , Shibuya Kazuhiko , Washida Nobuaki
Published: May 2003

The rate coefficient for the reaction of CCl3 radicals with ozone has been measured at 303 ± 2 K. The CCl3 radicals were generated by the pulsed laser photolysis of carbon tetrachloride at 193 nm. The time profile of CCl3 concentration was monitored with a photoionization mass spectrometer. Addition of the O3–O2 mixture to this system caused a decay of the CCl3 concentration because of the reactions of CCl3 + O3 → products (5) and CCl3 + O2 → products (4). The decay of signals from the CCl3 radical was measured in the presence and absence of ozone. In the absence of ozone, the O3–O2 mixture was passed through a heated quartz tube to convert the ozone to molecular oxygen. Since the rate coefficient for the reaction of CCl3 + O2 could be determined separately, the absolute rate coefficient for reaction (5) was obtained from the competition among these reactions. The rate coefficient determined for reaction (5) was (8.6 ± 0.5) × 10−13 cm3 molecule−1 s−1 and was also found to be independent of the total pressure (253–880 Pa of N2). This result shows that the reaction of CCl3 with O3 cannot compete with its reaction with O2 in the ozone layer. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 310–316, 2003
A shock tube study of the reaction NH2 + CH4 → NH3 + CH3 and comparison with transition state theory
Authors: Song Soonho , Golden David M. , Hanson Ronald K. , Bowman Craig T. , Senosiain Juan P. , Musgrave Charles B. , Friedrichs Gernot
Published: May 2003

The rate coefficient for NH2 + CH4 → NH3 + CH3 (R1) has been measured in a shock tube in the temperature range 1591–2084 K using FM spectroscopy to monitor NH2 radicals. The measurements are combined with a calculation of the potential energy surface and canonical transition state theory with WKB tunneling to obtain an expression for k1 = 1.47 × 103 T 3.01 e−5001/T(K) cm3 mol−1 s−1 that describes available data in the temperature range 300 –2100 K. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 304–309, 2003
New technique for generating high concentrations of gaseous OH radicals in relative rate measurements
Authors: Chen L. , Kutsuna S. , Tokuhashi K. , Sekiya A.
Published: May 2003

We have developed a technique for generating high concentrations of gaseous OH radicals in a reaction chamber. The technique, which involves the UV photolysis of O3 in the presence of water vapor, was used in combination with the relative rate method to obtain rate constants for reactions of OH radicals with selected species. A key improvement of the technique is that an O3/O2 (3%) gas mixture is continuously introduced into the reaction chamber, during the UV irradiation period. An important feature is that a high concentration of OH radicals [(0.53–1.2) × 1011 radicals cm−3] can be produced during the irradiation in continuous, steady‐state experiment. Using the new technique in conjunction with the relative rate method, we obtained the rate constant for the reaction of CHF3 (HFC‐23) with OH radicals, k1. We obtained k1(298 K) = (3.32 ± 0.20) × 10−16 and determined the temperature dependence of k1 to be (0.48 ± 0.13) × 10−12 exp[−(2180 ± 100)/T] cm3 molecule−1 s−1 at 253–328 K using CHF2CF3 (HFC‐125) and CHF2Cl (HCFC‐22) as reference compounds in CHF3–reference–H2O gas mixtures. The value of k1 obtained in this study is in agreement with previous measurements of k1. This result confirms that our technique for generating OH radicals is suitable for obtaining OH radical reaction rate constants of ∼10−16 cm3 molecule−1 s−1, provided the rate constants do not depend on pressure. In addition, it also needed to examine whether the reactions of sample and reference compound with O3 interfere the measurement when selecting this technique. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 317–325, 2003
A transient coastal wetland: from estuarine to supratidal conditions in less than 2000 years—Boca do Rio, Algarve, Portugal
Authors: Allen H. D.
Published: May 2003

Palaeoecological analysis of a 3 m sediment core from a coastal site in the western Algarve, near Lagos, Portugal, reveals the changing ecological characteristics of the wetland environment during the late Holocene. The dinoflagellate record and sedimentary characteristics show that approximately 2000 years ago the modern Boca do Rio wetlands were an estuary. By about 1200 14C years BP, transition to a lower energy environment was taking place. The pollen record at this time indicates the existence of typical salt marsh vegetation. There is a likely hiatus in the sedimentary record caused by the tsunami associated with the Lisbon earthquake of ad 1755. A barrier lake, impounded by tsunami deposits, existed for approximately 60 years before being breached, followed by a reoccurrence of saline conditions. A comparison of the mineral magnetic signature of the sediments with that of soil samples from the catchment suggests a relatively local provenance for some of the sediments, rather than the highly erodible Carboniferous rocks of the Algarve's Serra uplands. However, it is also suggested that there is a biogenic component to the magnetic mineralogy. Coastal wetlands are among the most vulnerable Mediterranean environments. The history and future of the Boca do Rio wetlands is examined in the context of alluviation history, rising sea levels, both past and future, and catchment land use. Changing patterns of cultivation, irrigation and land abandonment during the last 50 years are likely to have increased water demands within the catchment and therefore decreased river discharge to the wetlands. Consequently, the continued existence of the wetlands in their present form is in doubt, despite being part of a protected natural park. Copyright © 2003 John Wiley & Sons, Ltd.
Erodibility of soils of the upper rainforest zone, southeastern Nigeria
Authors: Igwe C. A.
Published: May 2003

The susceptibility of some soils in the high rainfall zone of Nigeria to soil erosion must be measured regularly for better soil management. A number of techniques have been adopted for the determination of this soil loss parameter. The aim of this study is to determine the soil characteristics that relate significantly to erodibility. Soil samples collected from 0–20 cm depth from 10 different locations in the upper rainforest area were analysed for particle size distribution, water‐stable aggregates, exchangeable cations, organic carbon, soil dispersion and aggregating indices. The soils are mainly Acrisols, Nitosols, Gleysols and Ferralsol in the FAO classification while their textures are sands to sandy‐clay‐loam. They are very unstable in water as reflected in the higher values of WSA >0·50 mm and the mean‐weight diameter that ranged from 0·50 to 2·03 mm. The dispersion ratio for the soils are between 0·26 and 0·69 while clay dispersion ratio also ranged from 0·24 to 0·80. Revised universal soil loss equation (RUSLE) erodibility model values (K) were from 0·03 to 0·06 Mg h MJ−1 mm−1. These parameters can be effectively used in predicting soil erodibility, though their predictability varied in ranking of soil erodibility. In spite of this variability these indices can be used for potential erosion hazard determination by agricultural extension staff to avoid crop failures and other negative influence of soil erosion. The soil parameters are easy to determine and will be a valuable instrument when faster approaches to erosion control measures are required. Copyright © 2003 John Wiley & Sons, Ltd.
Changes in soil fertility and Striga hermonthica prevalence associated with legume and cereal cultivation in the Sudan savannah zone of Ghana
Authors: Abunyewa A. A. , Padi F. K.
Published: May 2003

In the Sudano–Sahelian zones of West Africa, cultivated land is degraded due to reduced fallow periods and Striga hermonthica (Del.) Benth. infestation, and poses a serious threat to sustainable food production. To provide options for addressing these problems, we investigated the possibility of replacing the short fallow periods with food legume cultivation. We tested this in two farming communities within the Sudan savannah zone of Ghana. In the 1997 and 1998 cropping seasons, selected farmers within each community planted soybean [Glycine max. (L.) Merr.] or bambara groundnuts [Vigna subterranea (L.) Verdc.] on continuously cropped, Striga‐infested farmlands, whereas lands that were maintained under two or three years of bush fallowing were planted to millet [Pennisetum glaucum (L.) R. Br.] or sorghum [Sorghum bicolor (L.) Moench]. Analysis of soil sampled from 0–15 cm (plough layer) revealed that contents of major plant nutrients were inadequate to support long‐term crop production. Within each farming community, total nitrogen content at initial sampling showed significant negative correlation with the number of Striga seeds in the plough layer. Under legume cultivation, soil organic carbon content increased and the number of Striga seeds per square metre decreased in both communities from a mean value of 28 183 seeds m−2 to 8185 seeds m−2. Under cereal cultivation Striga seed density increased from 9383 seeds m−2 to 16 696 seeds m−2. The study provides evidence that introduction of food legume cultivation on farmlands with high S. hermonthica infestation as an alternative to bush fallow system could help achieve sustainable crop production in the Sudan savannah zones of sub‐Saharan Africa. Copyright © 2003 John Wiley & Sons, Ltd.
The use of coal fly ash in sodic soil reclamation
Authors: Kumar D. , Singh B.
Published: May 2003

An experiment was conducted for two years in northwest India to explore the feasibility of using coal fly ash for reclamation of waterlogged sodic soils and its resultant effects on plant growth in padi–wheat rotation. The initial pH, electrical conductivity, exchangeable sodium percentage and sodium adsorption ratio of the experimental soil were 9.07, 3.87 dS m−1, 26.0 and 4.77 (me l)−1/2, respectively. The fly ash obtained from electrostatic precipitators of thermal power plant had a pH of 5.89 and electrical conductivity of 0.88 dS m−1. The treatments comprised of fly ash levels of 0.0, 1.5, 3.0, 4.5, 6.0 and 7.5 per cent, used alone as well as in combination with 100, 80, 60, 40, 20 and 10 per cent gypsum requirement of the soil, respectively. There was a slight reduction in soil pH while electrical conductivity of the soil decreased significantly with fly ash as measured after padi and wheat crops. The sodium adsorption ratio of the soil decreased with increasing fly ash levels, while gypsum treatments considerably added to its favourable effects. Fly ash application increased the available elemental status of N, K, Ca, Mg, S, Fe, Mn, B, Mo, Al, Pb, Ni, Co, but decreased Na, P and Zn in the soil. An application of fly ash to the soil also increased the concentrations of above elements except Na, P and Zn in the seeds and straw of padi and wheat crops. The available as well as elemental concentrations in the plants was maximum in the 0 per cent fly ash + 100 per cent gypsum requirement treatment except Na and heavy elements like Ni, Co, Cr. The treatment effects were greater in the fly ash + gypsum requirement combinations as compared to fly ash alone. Saturated hydraulic conductivity and soil water retention generally improved with the addition of fly ash while bulk density decreased. Application of fly ash up to 4.5 per cent level increased the straw and grain yield of padi and wheat crops significantly in both years. The results indicated that for reclaiming sodic soils of the southwest Punjab, gypsum could possibly be substituted up to 40 per cent of the gypsum requirement with 3.0 per cent acidic fly ash. Copyright © 2003 John Wiley & Sons, Ltd.
Sodium removal from a calcareous saline–sodic soil through leaching and plant uptake during phytoremediation
Authors: Qadir M. , Steffens D. , Yan F. , Schubert S.
Published: May 2003

Saline–sodic and sodic soils are characterized by the occurrence of sodium (Na+) to levels that can adversely affect several soil properties and growth of most crops. As a potential substitute of cost‐intensive chemical amelioration, phytoremediation of such soils has emerged as an efficient and low‐cost strategy. This plant‐assisted amelioration involves cultivation of certain plant species that can withstand ambient soil salinity and sodicity levels. It relies on enhanced dissolution of native calcite within the root zone to provide adequate Ca2+ for the Na+Ca2+ exchange at the cation exchange sites. There is a lack of information for the Na+ balance in terms of removal from saline–sodic soils through plant uptake and leaching during the phytoremediation process. We carried out a lysimeter experiment on a calcareous saline–sodic soil [pH of saturated soil paste (pHs) = 7.2, electrical conductivity of the saturated paste extract (ECe) = 4.9 dS m−1, sodium adsorption ratio (SAR) = 15.9, CaCO3 = 50 g kg−1]. There were three treatments: (1) control (without application of a chemical amendment or crop cultivation), (2) soil application of gypsum according to the gypsum requirement of the soil and (3) planting of alfalfa (Medicago sativa L.) as a phytoremediation crop. The efficiency of treatments for soluble salt and Na+ removal from the soil was in the order: gypsum ≈ alfalfa > control. In the phytoremediation treatment, the amount of Na+ removed from the soil through leaching was found to be the principal cause of reduction in salinity and sodicity. Copyright © 2003 John Wiley & Sons, Ltd.
Offsetting global CO2 emissions by restoration of degraded soils and intensification of world agriculture and forestry
Authors: Lal R.
Published: May 2003

Increase in atmospheric concentration of CO2 from 285 parts per million by volume (ppmv) in 1850 to 370 ppm in 2000 is attributed to emissions of 270 ± 30 Pg carbon (C) from fossil fuel combustion and 136 ± 55 Pg C by land‐use change. Present levels of anthropogenic emissions involve 6·3  Pg C by fossil fuel emissions and 1·8 Pg C by land‐use change. Out of the historic loss of terrestrial C pool of 136 ± 55 Pg, 78 ± 12 Pg is due to depletion of soil organic carbon (SOC) pool comprising 26 ± 9 Pg due to accelerated soil erosion. A large proportion of the historic SOC lost can be resequestered by enhancing the SOC pool through converting to an appropriate land use and adopting recommended management practices (RMPs). The strategy is to return biomass to the soil in excess of the mineralization capacity through restoration of degraded/desertified soils and intensification of agricultural and forestry lands. Technological options for agricultural intensification include conservation tillage and residue mulching, integrated nutrient management, crop rotations involving cover crops, practices which enhance the efficiency of water, plant nutrients and energy use, improved pasture and tree species, controlled grazing, and judicious use of inptus. The potential of SOC sequestration is estimated at 1–2 Pg C yr−1 for the world, 0·3–0·6 Pg C yr−1 for Asia, 0·2–0·5 Pg C yr−1 for Africa and 0·1–0·3 Pg C yr−1 for North and Central America and South America, 0·1–0·3 Pg C yr−1 for Europe and 0·1–0·2 Pg C yr−1 for Oceania. Soil C sequestration is a win–win strategy; it enhances productivity, improves environment moderation capacity, and mitigates global warming. Copyright © 2003 John Wiley & Sons, Ltd.
Dissolution and Enzymatic Degradation Studies Before and After Artificial Ageing of Silk‐ or Linen‐Reinforced Gelatin Laminates, 2
Authors: Boyanova M. , Stambolieva N. , Apostolov A. A. , Fakirov S.
Published: May 2003

Biodegradable laminates based on gelatin and on gelatin/starch blend reinforced with fabrics (silk or linen) were prepared by melt pressing. Due to crosslinking during the thermal treatment and in some cases, to additional crosslinking with methylenedi(p‐phenyl) diisocyanate, the fresh and artificially aged samples demonstrated improved mechanical properties, as reported previously. In Part 1 of this study on the environmental behavior of these new laminated composites, the simple dissolution in a buffer solution or water of fresh and artificially aged samples was considered. During this treatment soluble, i.e., uncrosslinked molecules were removed leaving a product resulting from addition reactions and consequent crosslinking. These processes take place during the melt pressing at 180 °C and cause a decreased solubility of gelatin. The present Part 2 deals with the enzymatic treatment of the same samples. We have implicitly shown that the gelatin moiety of the laminates undergoes proteolysis and that this process depends on the laminate composition. At the end of the treatment the enzymatic buffer solution contains only peptides and virtually no high‐molecular gelatin. The degrees of degradation vs. time dependencies differ for water and enzymatic treatment of the samples, indicating different processes in either treatment. The time‐course curves of the enzymatic treatment of different laminates and the kinetic parameters derived therefrom were analyzed. Thereby the effect of many factors on the accessibility of the gelatin moiety to proteolysis was shown. These factors are: temperature treatment, artificial ageing, the nature of the reinforcing fabrics, the “additional” crosslinking with methylenedi(p‐phenyl) diisocyanate, etc. The gelatin‐linen laminate is the most sensitive to crosslinking. There is a tendency that the crosslinking smears the differences in the time‐course of the absorption behavior curves of the different samples.

Degree of degradation, β′, (related to only the gelatin) vs. time, t, for laminates: (a) uncrosslinked gelatin‐linen; (b) crosslinked gelatin‐linen; (c) uncrosslinked gelatin‐silk; (d) crosslinked gelatin‐silk.

magnified image

Degree of degradation, β′, (related to only the gelatin) vs. time, t, for laminates: (a) uncrosslinked gelatin‐linen; (b) crosslinked gelatin‐linen; (c) uncrosslinked gelatin‐silk; (d) crosslinked gelatin‐silk.
Reactive Compatibilization of Polyamide 6 with Isocyanate Functionalized Ethylene‐Propylene Copolymer
Authors: Ding Yongtao , Xin Zhirong , Gao Ying , Xu Xiaodong , Yin Jinghua , Costa Giovanna , Falqui Luciano , Valenti Barbara
Published: May 2003

Reactive compatibilization of ethylene‐propylene copolymer functionalized with allyl (3‐isocyanato‐4‐tolyl) carbamate (TAI) isocyanate (EPM‐g‐TAI) and polyamide 6 (PA6) was investigated in this paper. FTIR analysis revealed the evidence of a chemical reaction between the end groups of PA6 and EPM‐g‐TAI. Thermal, rheological, morphological, and mechanical properties of the resultant system were examined. DSC analysis indicated that the crystallization of PA6 in PA6/EPM‐g‐TAI blends was inhibited, due to the chemical reaction that occurs at the interface of PA6 and EPM‐g‐TAI. Rheological measurement showed that complex viscosity and storage modulus of PA6/EPM‐g‐TAI were both dramatically enhanced compared to those of PA6/EPM at the same blending composition. After examining the morphology of both blending systems, smaller particle size, more homogeneous distribution of domains and improved interfacial adhesion between matrix and domains were observed in the compatibilized system. Mechanical properties such as tensile strength, Young's modulus, flexural strength and modulus, as well as notched and un‐notched impact strength of PA6/EPM‐g‐TAI blends were also found to improve gradually with increasing the content of grafted TAI.

Tensile modulus of the blends versus rubber content.

magnified image

Tensile modulus of the blends versus rubber content.
Reactions of polypeptide ions with electrons in the gas phase
Authors: Zubarev Roman A.
Published: May 2003

I.
Introduction
58

A.  Challenges in the Gas‐Phase Fragmentation of Polypeptides
58

B.  Ion–Electron Interactions
58

C.  Nomenclature
59

 II.
Instrumental Realization and Applications
60

III.
Electron‐Capture Dissociation
61

A.  Electron Capture
61

B.  NCα Bond Cleavage
62

C.  SS Bond Reduction
64

D.  Dissociation of Strong Bonds in the Presence of Weak Bonding
65

E.  Frequencies of NCα Bond Cleavage
67

 IV.
Electronic Excitation
68

A.  Hot‐Electron‐Capture Dissociation (HECD)
68

B.  Electronic Excitation Dissociation (EED)
69

  V.
Vibrational Excitation
70

A.  Vibrational Excitation of Even‐Electron Species
70

B.  Vibrational Excitation of Radical Species
71

 VI.
Electron Detachment
72

A.  Ionization
72

B.  Electron‐Detachment Dissociation (EDD)
73

VII.
Conclusions
74

References

74

Reactions of electrons in the energy range below 70 eV with polypeptide cations and anions are reviewed, as well as their applications for the structural analysis of polypeptides. At very low energies (≤ 0.1 eV), the major outcome is electron‐capture dissociation (ECD) of SS and backbone NCα bonds, leading to c′ and z· fragments. ECD is useful in sequencing and characterization of post‐translational modifications (PTMs), because c′, z· fragmentation is abundant and the fragments usually retain labile groups. Electron capture at higher energies (3–13 eV) induces secondary fragmentation in radical z· fragments; this hot ECD (HECD) allows one to distinguish between the isomeric leucine and isoleucine residues. If a hot electron is not captured, then the induced electronic excitation converts internally into vibrational energy, resulting in fragmentation of the C(O)N backbone bond (so‐called EIEIO process). Above 9–10 eV, further ionization of n‐charged cations occurs. If the formed (n + 1)+· cations capture electrons, then the CαC backbone bond is usually broken. For anions that collide with ≈20 eV electrons, the ejection of an electron leads to the creation of a radical positive charge (hole) that recombines internally with a negative charge. Such recombination leads to various backbone bond cleavages. This electron‐detachment dissociation (EDD) is analogous to ECD for negative ions. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:57–77, 2003; Published online in Wiley InterScience (www.interscience.wiley.com)
Identification of distinct and common gene expression changes after oxidative stress and gamma and ultraviolet radiation
Authors: Heinloth Alexandra N. , Shackelford Rodney E. , Innes Cynthia L. , Bennett Lee , Li Leping , Amin Rupesh P. , Sieber Stella O. , Flores Kristina G. , Bushel Pierre R. , Paules Richard S.
Published: May 2003

The human genome is exposed to many different kinds of DNA‐damaging agents. While most damage is detected and repaired through complex damage recognition and repair machineries, some damage has the potential to escape these mechanisms. Unrepaired DNA damage can give rise to alterations and mutations in the genome in an individual cell, which can result in malignant transformation, especially when critical genes are deregulated. In this study, we investigated gene expression changes in response to oxidative stress, gamma (γ) radiation, and ultraviolet (UV) radiation and their potential implications in cancer development. Doses were selected for each of the three treatments, based on their ability to cause a similar G1 checkpoint induction and slow down in early S‐phase progression, as reflected by a comparable reduction in cyclin E–associated kinase activity of at least 75% in logarithmically growing human dermal diploid fibroblasts. To investigate gene expression changes, logarithmically growing dermal diploid fibroblasts were exposed to either γ radiation (5 Gy), oxidative stress (75 μM of tert‐butyl hydroperoxide (t‐butyl‐OOH)), or UV radiation (UVC) (7.5 J/m2) and RNA was harvested 6 h after treatment. Gene expression was analyzed using the NIEHS Human ToxChip 2.0 with approximately 1901 cDNA clones representing known genes and expressed sequence tags (ESTs). We were able to identify common and distinct responses in dermal diploid fibroblasts to the three different stimuli used. Within our analysis, gene expression profiles in response to γ radiation and oxidative stress appeared to be more similar than profiles expressed after UV radiation. Interestingly, equivalent cyclin E–associated kinase activity reduction with all the three treatments was associated with greater transcriptional changes after UV radiation than after γ radiation and oxidative stress. While samples treated with UV radiation displayed modulations of their mitogen activated protein kinase (MAPK) pathway, γ radiation had its major influence on cell‐cycle progression in S‐phase and mitosis. In addition, cell cultures from different individuals displayed significant differences in their gene expression responses to DNA damage. Published 2003 Wiley‐Liss, Inc.
Inactivation of helicase‐like transcription factor by promoter hypermethylation in human gastric cancer
Authors: Leung Wai K. , Yu Jun , Bai Alfa H.C. , Chan Michael W.Y. , Chan Ka‐Kui , To Ka‐Fai , Chan Francis K.L. , Ng Enders K.W. , Chung S.C. Sydney , Sung Joseph J.Y.
Published: May 2003

Helicase‐like transcription factor (HLTF), a member of the SWI/SNF (mating type switching/sucrose nonfermenting) chromatin‐remodeling complex, is recently found to be inactivated by promoter hypermethylation in human colorectal cancer. However, the role of this putative tumor suppressor gene in other tumors has not been determined. We evaluated the role of HLTF promoter hypermethylation in gastric cancer. Expression of HLTF was examined by reverse‐transcription (RT)–polymerase chain reaction (PCR), and promoter hypermethylation in HLTF was determined by methylation–specific PCR. Bisulfite DNA sequencing was performed to determine the detailed methylation profiles of the promoter region. HLTF expression was lost in two of five gastric cell lines and in 13 (28%) of 46 primary gastric cancers. Accordingly, promoter hypermethylation was detected in the two cell lines and in nine of 13 gastric cancer samples. Of the ten normal gastric specimens and ten paired adjacent nonneoplastic tissues, methylation was detected in only one adjacent nonneoplastic tissue. Bisulfite DNA sequencing of the promoter region of HLTF showed that the CpG island was densely methylated in cell lines and cancer samples; this also appeared to correlate with expression level. Treatment of gastric cell lines that lacked HLTF expression with the demethylating agent 5‐azacytidine (5‐azaDC) restored HLTF expression. These results suggest that HLTF promoter hypermethylation is frequently demonstrated in human gastric cancer, and inactivation of HLTF or the chromatin‐remodeling complex may play a crucial role in gastric carcinogenesis. © 2003 Wiley‐Liss, Inc.
Regulation of cell morphology and adhesion by the tuberous sclerosis complex (TSC1/2) gene products in human kidney epithelial cells through increased E‐cadherin/β‐catenin activity
Authors: Li Shaowei , Braverman Richard , Li Hongzhen , Vass William C. , Lowy Douglas R. , DeClue Jeffrey E.
Published: May 2003

We investigated the effects of overexpression of the tuberous sclerosis‐1 and ‐2 (TSC1/2) gene products (hamartin and tuberin, respectively) in the human kidney epithelial cell line 293 with an inducible expression system. As we had observed previously in fibroblasts, 293 cells overexpressing hamartin and/or tuberin grew more slowly in vitro. However, here we also observed that the 293 overexpressing cells underwent a dramatic morphological change in which groups of cells formed compact clusters. The overexpressing cells also displayed decreased dissociation and increased reaggregation in vitro. These changes were found to be associated with an increased level of E‐cadherin, which is known to regulate cell‐cell interactions in epithelial cells, and of its binding partner β‐catenin. Consistent with the role of E‐cadherin in these effects, we found that the observed changes in 293 cell morphology, dissociation, and adhesion were calcium‐dependent, and were reproduced by overexpression of E‐cadherin. In contrast, overexpression of TSC1 in rat embryo fibroblasts, which lack E‐cadherin, failed to elicit the same changes as in 293 cells. We conclude that the hamartin/tuberin complex exerted a direct effect on the morphology and adhesive properties of 293 cells through regulation of the level and/or activity of cellular E‐cadherin/β‐catenin. © 2003 Wiley‐Liss, Inc.
Modulation of the angiogenesis response through Ha‐ras control, placenta growth factor, and angiopoietin expression in mouse skin carcinogenesis
Authors: Larcher Fernando , Franco Marcela , Bolontrade Marcela , Rodriguez‐Puebla Marcelo , Casanova Llanos , Navarro Manuel , Yancopoulos George , Jorcano José L , Conti Claudio J.
Published: May 2003

Tumor angiogenesis is governed by a complex balance of positive and negative angiogenic factors. Development of chemically‐induced mouse skin tumors appears to be highly dependent on an early burst of neovascularization. We have previously shown that Ha‐ras–driven vascular endothelial growth factor (VEGF) expression plays a pivotal role in this process. However, the status of other critical positive and negative angiogenic factors throughout skin tumorigenesis has not been studied to the same extent. In the present study, we show that another VEGF family member, placenta growth factor (PlGF), was highly upregulated at all tumor stages in a ras‐dependent manner. The study of angiopoietin‐1 (Ang‐1) and angiopoietin‐2 (Ang‐2), ligands of receptor tyrosine kinase 2 (Tie‐2), showed that while stroma–derived Ang‐2 was increased, epidermal Ang‐1 expression was completely abolished at early papilloma formation. Studies using epidermal tumor cell lines suggest that the disappearance of Ang‐1 also depends on ras activation, extending the plethora of events controlled by this oncogene in mouse skin carcinogenesis. Our results indicated that tumor development occurred in a strong angiogenesis‐prone scenario in which PlGF and Ang‐2 acted cooperatively with VEGF, whereas the negative or stabilizing effect of Ang‐1 was abrogated. A time‐course sequence of expression of angiogenic factors expressed throughout tumor growth, as well as the identification of key signaling molecules triggering the angiogenic response, may contribute to the development and testing of antiangiogenic therapeutic strategies with this in vivo tumor model. © 2003 Wiley‐Liss, Inc.
Mutation analysis of CDP, TP53, and KRAS in uterine leiomyomas
Authors: Patrikis Maria I. , Bryan Emma J. , Thomas Nicola A. , Rice Greg E. , Quinn Michael A. , Baker Mark S. , Campbell Ian G.
Published: May 2003

Leiomyomas are the most common gynecologic tumors in women, but very little is known about their molecular pathology. We used single‐stranded conformational polymorphism/heteroduplex analysis to analyze 42 unselected uterine leiomyomas for somatic mutations in all coding exons of the gene encoding CCAAT displacement protein (CDP), as well as exons 5–8 of TP53 and codons 1–36 and 38–80 of KRAS. No somatic mutations were identified in either TP53 or KRAS, indicating that disregulation of these genes is not required for leiomyomas development. Aberrant band shifts were identified in CDP, but these were all germline nonpathogenic variants that have been reported previously. There is good functional and genetic evidence indicating that CDP is a leiomyoma suppressor, but our data suggested that somatic mutations in this gene were rare in unselected uterine leiomyomas. It is possible that CDP belongs to a class of tumor suppressor in which loss of only one copy of the gene, either by genetic or epigenetic mechanisms, is sufficient to allow tumor growth. © 2003 Wiley‐Liss, Inc.
Formation of an active form of the interleukin‐2/15 receptor β‐chain by insertion of the intracisternal A particle in a radiation‐induced mouse thymic lymphoma and its role in tumorigenesis
Authors: Ukai Hideki , Ishii‐Oba Hiroko , Ukai‐Tadenuma Maki , Ogiu Toshiaki , Tsuji Hideo
Published: May 2003

Although many reports suggest that aberrant regulation of cytokine signaling pathways via the interleukin‐2 receptor (IL‐2R) induces tumorigenic transformation, constitutively active IL‐2R in tumors has not been reported. We searched for genomic alteration of the IL‐2/15R β‐subunit gene (IL‐2/15Rβ) in cytokine‐independent cell lines established from radiation‐induced mouse thymic lymphomas. In the TL34 cell line and its primary tumor, one of the IL‐2/15Rβ alleles was rearranged by the insertion of an intracisternal A particle (IAP) retrotransposon. The IAP‐IL2/15Rβ chimeric gene expressed chimeric mRNA in which IAP‐coding Gag‐Pol mRNA was fused to IL‐2/15Rβ mRNA and coded for Gag‐Pol‐IL‐2/15Rβ chimeric protein. Forced expression of the Gag‐Pol‐IL‐2/15Rβ chimeric cDNA in a mouse cytotoxic T‐cell line (CTLL‐2) converted IL‐2‐dependent cell growth to IL‐2‐independent growth, suggesting that the chimeric protein activates some of the IL‐2 signaling pathways necessary for cell proliferation. Downregulation of the expression of the Gag‐Pol‐IL‐2/15Rβ chimeric protein in TL34 by antisense RNA inhibited cell growth, and concomitantly reduced the level of c‐myc protein. These results suggest that the Gag‐Pol‐IL‐2/15Rβ is a constitutively active form that transmits proliferative signals by expressing downstream target genes, including c‐myc. Thus, we demonstrated that the chimeric receptor gene produced by the insertion of an IAP functions as an oncogene by providing IL‐2‐independent autonomous growth potential. © 2003 Wiley‐Liss, Inc.
MRI‐guided focused ultrasound surgery in the brain: Tests in a primate model
Authors: McDannold Nathan , Moss Mark , Killiany Ron , Rosene Douglas L. , King Randy L. , Jolesz Ferenc A. , Hynynen Kullervo
Published: May 2003

MRI‐guided focused ultrasound was tested in the brains of rhesus monkeys. Locations up to 4.8 cm deep were targeted. Focal heating was observed in all cases with MRI‐derived temperature imaging. Subthreshold heating was observed at the focus when the ultrasound beam was targeted with low power sonications, and in the ultrasound beam path during high‐power exposures. Lethal temperature values and histologically confirmed tissue damage were confined to the focal zone (e.g., not in the ultrasound beam path), except when the focus was close to the bone. In that case, damage to the neighboring brain tissue was observed. Focal lesions were observed on histological examination and, in some cases, in MR images acquired immediately after the ultrasound exposures. The capabilities demonstrated in this study will be of benefit for clinical ultrasound therapies in the brain. Magn Reson Med 49:1188–1191, 2003. © 2003 Wiley‐Liss, Inc.
Increased diffusion sensitivity with hyperechos
Authors: Frank Lawrence R. , Wong Eric C. , Liu Thomas T. , Buxton Richard B.
Published: May 2003

It is shown that the introduction of a 180° refocusing pulse into a standard diffusion weighted stimulated echo sequence is equivalent to the simplest hyperecho sequence with identical diffusion weighting but equal or greater signal‐to‐noise (SNR) and thus equal or greater diffusion contrast. For high b‐value imaging, the hyperecho sequence thus possesses the high diffusion contrast in the presence of small T1/T2 ratios characteristic of stimulated echo sequences but with less than the 50% loss in SNR that is associated with the stimulated echo. For low b‐value imaging, the hyperecho signal converges to that of the standard spin echo. The advantages of the two‐pulse diffusion weighted hyperecho sequence are demonstrated theoretically. Experimental results are shown in the application to high angular resolution diffusion encoding (HARD) in normal human brain. Magn Reson Med 49:1098–1105, 2003. Published 2003 Wiley‐Liss, Inc.
Magnetic resonance imaging of gastric cancer in Tff1 knock‐out mice
Authors: Berr Stuart S. , Roche James K. , El‐Rifai Wa'el , Smith Michael F. , Powell Steven M.
Published: May 2003

In this work, the use of MRI to stage gastric neoplasia in a mouse model of spontaneous gastric cancer is demonstrated. The methodology involves 1) the use of deuterated water (2H2O) to distend the stomach, and to provide negative contrast between the stomach and the lumen without inducing susceptibility‐based field shifts; 2) GlucaGen® to minimize motion artifacts that arise from peristalsis; and 3) Gd‐DTPA to enhance contrast between the dysplasia/tumor and the normal wall. Initial images are presented from a Tff1 −/− homozygous knock‐out model of gastric cancer and a heterozygous C57BL6/J control mouse. There are clear differences between the two types of animals in the MR appearance of the stomach. The distended stomach of the control mouse has a smooth perimeter and a thin wall, and an absence of nodules. The stomach of the Tff1 −/− mouse demonstrates a thickened wall; a jagged, irregular surface; and protruding nodules that are bright after injection of Gd‐DTPA. Magn Reson Med 49:1033–1036, 2003. © 2003 Wiley‐Liss, Inc.
Image‐based tracking of optically detunable parallel resonant circuits
Authors: Eggers Holger , Weiss Steffen , Boernert Peter , Boesiger Peter
Published: May 2003

In this work strategies for the robust localization of parallel resonant circuits are investigated. These strategies are based on the subtraction of two images, which ideally differ in signal intensity at the positions of the devices only. To modulate their signal amplification, and thereby generate the local variations, the parallel resonant circuits are alternately detuned and retuned during the acquisition. The integration of photodiodes into the devices permits their fast optical switching. Radial and spiral imaging sequences are modified to provide the data for the two images in addition to those for a conventional image in the same acquisition time. The strategies were evaluated by phantom experiments with stationary and moving catheter‐borne devices. In particular, rapid detuning and retuning during the sampling of single profiles is shown to lead to a robust localization. Moreover, this strategy eliminates most of the drawbacks usually associated with image‐based tracking, such as low temporal resolution. Image‐based tracking may thus become a competitive (if not superior) alternative to projection‐based tracking of parallel resonant circuits. Magn Reson Med 49:1163–1174, 2003. © 2003 Wiley‐Liss, Inc.