bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of amphioxus amphivent, an evolutionarily conserved marker for chordate ventral mesoderm
Authors: Kozmik Zbynek , Holland Linda Z. , Schubert Michael , Lacalli Thurston C. , Kreslova Jana , Vlcek Cestmir , Holland Nicholas D.
Published: August 2002

Summary: Structure and developmental expression are described for amphioxus AmphiVent, a homolog of vertebrate Vent genes. In amphioxus, AmphiVent‐expressing ventral mesoderm arises at midneurula by outgrowth from the paraxial mesoderm, but in vertebrates, Vent‐expressing ventral mesoderm originates earlier, at the gastrula stage. In other embryonic tissues (nascent paraxial mesoderm, neural plate, endoderm, and tailbud), AmphiVent and its vertebrate homologs are expressed in similar spatiotemporal domains, indicating conservation of many Vent gene functions during chordate evolution. The ventral mesoderm evidently develops precociously in vertebrates because their relatively large embryos probably require an early and extensive deployment of the mesoderm‐derived circulatory system. The vertebrate ventral mesoderm, in spite of its strikingly early advent, still resembles the nascent ventral mesoderm of amphioxus in expressing Vent homologs. This coincidence may indicate that Vent homologs in vertebrates and amphioxus play comparable roles in ventral mesoderm specification. genesis 29:172–179, 2001. © 2001 Wiley‐Liss, Inc.
Cell populations and morphogenetic movements underlying formation of the avian primitive streak and organizer
Authors: Lawson Aaron , Schoenwolf Gary C.
Published: August 2002

Summary: The cell populations and morphogenetic movements that contribute to the formation of the avian primitive streak and organizer—Hensen's node—are poorly understood. We labeled selected groups of cells with fluorescent dyes and then followed them over time during formation and progression of the primitive streak and formation of Hensen's node. We show that (1) the primitive streak arises from a localized population of epiblast cells spanning the caudal midline of Koller's sickle, with the mid‐dorsal cells of the primitive streak arising from the midline of the epiblast overlying Koller's sickle and the deeper and more lateral primitive streak cells arising more laterally within the epiblast overlying the sickle, from an arch subtending about 30°; (2) convergent extension movements of cells in the epiblast overlying Koller's sickle contribute to formation of the initial primitive streak; and (3) Hensen's node is derived from a mixture of cells originating both from the epiblast just rostral to the incipient (stage 2) primitive streak and later from the epiblast just rostral to the elongating (stage 3a/b) primitive streak, as well as from the rostral tip of the progressing streak itself. Collectively, these results provide new information on the formation of the avian primitive streak and organizer, increasing our understanding of these important events of early development of amniotes. genesis 29:188–195, 2001. © 2001 Wiley‐Liss, Inc.
The role of genotype in determining the effects of cigarette smoking on pulmonary function
Authors: Tishler Peter V. , Carey Vincent J. , Reed Terry , Fabsitz Richard R.
Published: August 2002

The effect of cigarette smoking on pulmonary function is highly variable. Some heavy smokers retain normal pulmonary function and others experience profound pulmonary function loss. The role of genotype in this process is unknown. We tested for gene by environment interaction (GxE) in smoking‐associated loss of forced expiratory volume in one second (FEV1) using repeated pulmonary function and smoke‐exposure measures from 352 twin pairs enrolled in the NHLBI Male Veteran Twin Study. Inferences using global [Jinks and Fulker, 1970] and dichotomous [Ramakrishnan et al., 1992] procedures were supplemented with a new model for repeatedly observed twinships. The model facilitates testing of standard heritability hypotheses and families of hypotheses regarding the dependence of quantitative twin‐twin phenotypic similarity on continuously varying twin‐twin exposure concordance. The global and dichotomous procedures were suggestive of GxE in smoke‐associated loss of FEV1 (p < 0.01, p = 0.08, respectively). With the new model, overall twin‐twin correlation of FEV1 for concordant‐smoking MZ and DZ twin pairs was estimated at 0.71 and 0.34, respectively. For twins with little or no difference in cigarette use, the intra‐pair correlations of FEV1 did not differ according to cigarette exposure over a wide range of exposures (0 ‐ ≥ 200 pack years). Even great twin‐twin discordance in cigarette smoking (≥10 pack years) had little effect of correlations. We conclude that a constant factor, such as genotype, appears to be interposed between the environmental toxin (cigarette smoke) and phenotype (FEV1). Genet. Epidemiol. 22:272–282, 2002. © 2002 Wiley‐Liss, Inc.
The world's longest graptolite?
Authors: Loydell David K. , Loveridge Robert F.
Published: August 2002

An incomplete specimen of Stimulograptus halli 1.45 m long is recorded from the Aberystwyth Grits Formation north of Clarach, western mid‐Wales. This is the longest graptoloid graptolite known. Assuming a growth rate similar to that of modern Rhabdopleura it lived for at least 25 years. Copyright © 2001 John Wiley & Sons, Ltd.
Ostracode faunas of bottom sediments from the continental shelf, south Marmara Sea, NW Turkey, and their comparison with other shelf environments in the Mediterranean and Aegean regions
Authors: Nazik Atike
Published: August 2002

This study describes the ostracode faunal composition and distribution on the continental shelf of the southern Marmara Sea in Turkey. Twenty‐three bottom samples were collected from the shelf. These samples are characterized by silt‐clay (mud), sand and gravel in the studied area. A total of 46 species belonging to 32 genera were determined from these samples. Seven species were dominant from 46 ostracode species. Three assemblages were identified by their dominant species. These are characterized by: Costa edwardsii (Roemer); a mixed assemblage which consists of Cytheridea neapolitana Kollmann, Pterygocythereis ceratoptera (Bosquet), Tegmenia rugosa (Costa), Acanthocythereis hystrix (Reuss) and Xestoleberis communis (G.W. Müller); and Aurila convexa (Baird). The relations between the dominant species, lithology and CaCO3 concentration have been investigated, and the results are compared with other shelf environments within the Mediterranean and Aegean regions. Pterygocythereis, Costa, Tegmenia and Cytheridea are abundant in muddy substrates; Aurila and Acanthocythereis are abundant in sandy substrates. Acanthocythereis hystrix (Reuss), Aurila convexa (Baird), Buntonia subulata Ruggieri, Carinocythereis antiquata (Baird), Carinocythereis carinata (Roemer), Costa batei (Brady), Costa edwardsii (Roemer), Cytheridea neapolitana Kollmann, Celtia quadridentata (Baird), Loxoconcha rhomboidea (Fischer), Pterygocythereis jonesii (Baird) and Semicytherura acuticostata (Sars) are common, and similar species are recorded from other continental shelves of the Mediterranean. Copyright © 2001 John Wiley & Sons, Ltd.
Geochemical and Nd‐Sr‐Pb isotopic evidence on the origin and geodynamic evolution of mid‐Cretaceous continental arc volcanic rocks of the Spences Bridge Group, south‐central British Columbia
Authors: Smith Alan D. , Thorkelson Derek
Published: August 2002

The mid‐Cretaceous Spences Bridge Group (SBG) comprises a series of basaltic to rhyolitic lavas and related volcaniclastic rocks (Pimainus Formation) overlain by a succession of mainly amygdaloidal andesites (Spius Formation) related to the closure of the Methow–Tyaughton basin and accretion of the Insular terrane in the North American Cordillera. Geochemical variation in the SBG is related primarily to metasomatic processes in the mantle wedge. Pimainus lavas include low‐ to high‐K, tholeiitic and calc‐alkaline types, and have isotopic compositions (εNd(100Ma) = + 5.2 to + 7.0, εSr(100Ma) = − 10 to − 20, 206Pb/204Pb = 18.82 to 18.91, 207Pb/204Pb = 15.55 to 15.60, 208Pb/204Pb = 38.24 to 38.43) between the ranges for primitive arcs and accreted terrane crust. Crustal sources are identified only for some low–medium K dacite and rhyolite compositions. The occurrence of intermediate compositions with high MgO contents (up to 6 wt%) and the presence of adakitic trace element features in medium–high K felsic lavas attests to metasomatism of the mantle wedge by slab melts during Pimainus volcanism. Spius lavas have comparable K2O and Pb isotopic compositions to the Pimainus, even higher MgO (up to 9.2 wt%), and display a mild intraplate character in having up to 0.6 wt% P2O5, 15 ppm Nb, and 240 ppm Zr. Spius Nd−Sr isotopic compositions (εNd(100Ma) = + 5.3 to + 6.9, εSr(100Ma) = − 14 to − 25) define an array extending from Pimainus to alkaline seamount compositions. The low εSr values, elevated high field strength element contents, and moderate silica contents suggest Spius volcanism was related to the introduction of small melt fractions from the asthenosphere into the mantle wedge which had previously generated Pimainus melts. The range of compositional types in the Pimainus Formation constrains tectonic scenarios to include an elevated slab thermal regime, likely from approach of an ocean ridge system toward the continental margin. Spius volcanism may have been generated by asthenospheric upwelling triggered by slab window development or slab‐hinge roll‐back on closure of the Methow–Tyaughton basin. Copyright © 2002 John Wiley & Sons, Ltd.
Immunohistochemistry study of human vestibular nerve schwannoma differentiation
Authors: Hung Gene , Colton Joyce , Fisher Laurel , Oppenheimer Mark , Faudoa Rodolfo , Slattery William , Linthicum Fred
Published: August 2002

Differentiation of primary human vestibular nerve schwannomas (VS) caused by mutations of the NF2 gene was evaluated by examining the expression patterns of genes that are specifically expressed in different stages of Schwann cell lineage. In schwannoma cells that are not in contact with an axon, the expression levels of the major myelin sheath proteins, such as protein zero glycoprotein (P0), myelin basic protein (MBP), and peripheral myelin protein 22 (PMP22), were greatly reduced. However, high expression levels of nerve growth factor receptor (NGFR), neural cell adhesion molecule (N‐CAM), and cell adhesion molecule L1 (L1) were observed. In addition, expression of transcription factors Krox20, Krox24, and SCIP/Oct6 was also detected in the tumor cells. These results suggest that loss of the NF2 gene was responsible for the transformation of the Schwann cells into a neoplastic stage that has a similar genetic profile to the pro‐myelinating stage. Finally, the primary human vestibular schwannoma cells failed to be regulated and redifferentiated by a regenerating axon, when the human tumors were transplanted into sciatic nerve of nude rat. These results suggest that the NF2 gene might be involved in the differentiation of Schwann cells. GLIA 38:363–370, 2002. © 2002 Wiley‐Liss, Inc.
Neuroligin 3 is a vertebrate gliotactin expressed in the olfactory ensheathing glia, a growth‐promoting class of macroglia
Authors: Gilbert Mary , Smith Jeff , Roskams Angela‐Jane , Auld Vanessa J.
Published: August 2002

The molecular mechanisms that drive glia–glial interactions and glia–neuronal interactions during the development of the nervous system are poorly understood. A number of membrane‐bound cell adhesion molecules have been shown to play a role, although the precise nature of their involvement is unknown. One class of molecules with cell adhesive properties used in the nervous system is the serine‐esterase‐like family of transmembrane proteins. A member of this class, a glia‐specific protein called gliotactin, has been shown to be necessary for the development of the glial sheath in the peripheral nervous system of Drosophila melanogaster. Gliotactin is essential for the development of septate junctions in the glial sheath of individual and neighboring glia. Mutations that remove this protein result in paralysis and eventually death due to a breakdown in the glial‐based blood–nerve barrier. To study the role of gliotactin during vertebrate nervous system development, we have isolated a potential vertebrate gliotactin homologue from mice and rat and found that it corresponds to neuroligin 3. Using a combination of RT‐PCR and immunohistochemistry, we have found that neuroligin 3 is expressed during the development of the nervous system in many classes of glia. In particular neuroligin 3 is expressed in the olfactory ensheathing glia, retinal astrocytes, Schwann cells, and spinal cord astrocytes in the developing embryo. This expression is developmentally controlled such that in postnatal and adult stages, neuroligin 3 continues to be expressed at high levels in the olfactory ensheathing glia, a highly plastic class of glia that retain many of their developmental characteristics throughout life. GLIA 34:151–164, 2001. © 2001 Wiley‐Liss, Inc.
An age‐based comparison of chronic pain clinic patients
Authors: Wijeratne Chanaka , Shome Sushmita , Hickie Ian , Koschera Annette
Published: August 2002

Objective

The aim of this study was to compare demographic, illness and personality characteristics, and formal rates of mental disorder between younger (< 65 years) and older (≥ 65 years) patients attending a chronic pain clinic.

Method

Patients with non‐malignant pain of > 6 months' duration attending a specialist outpatient clinic were given a structured medical and psychiatric interview, and completed self‐report questionnaires assessing disability, personality style and attitudes to illness.

Results

Fifty patients (26 of whom were older) participated in the study. None of the older patients had experienced the onset of chronic pain before the age of 50 years. Although current and lifetime major depression were common in both groups, there was no specific association between age and depression. The younger group was more likely to have been injured prior to the onset of pain and to be seeking financial compensation, reported more physical and social disability, and was more likely to be preoccupied with somatic discomfort. The younger group was also more likely to be rated as displaying impulsive personality traits and the older group anxious traits, although there was no difference in neuroticism scores.

Conclusion

Despite a greater level of multiple medical morbidity and longer duration of pain, older patients with chronic pain were not more likely to suffer from concurrent depression, were less disabled and less somatically preoccupied than younger patients. There were sufficient differences in illness and psychological characteristics to suggest that the older patients represented an aetiologically distinct sub‐group, rather than patients with chronic pain of early onset who have simply grown old. Finally, the utility of DSM‐IV defined somatoform disorders, in particular pain disorder, is discussed. A model which integrates medical and psychological mechanisms is needed for clinical use. Copyright © 2001 John Wiley & Sons, Ltd
Enantioselective reduction of 2‐keto‐3‐haloalkane phosphonates by baker's yeast
Authors: Yuan Cheng‐ye , Wang Ke , Li Zu‐yi
Published: August 2002

Bioreduction of 3‐substituted‐2‐oxoal‐kanephosphonates by baker's yeast afforded 3‐substituted‐2‐hydroxy‐alkanephosphonates in moderate to good yields and ee value. These compounds could serve as useful chirons for the stereoselective synthesis of phosphorus analogs of biologically active molecules including R‐(—)‐3‐trimethylammonium‐2‐hydroxypropanoic acid and R‐(—)‐3‐ trimethylammonium‐2‐hydroxypropanoic acid. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:551–556, 2001
Reactions of 2,3‐dihydro‐1H‐1,5‐benzodiazepines and chloroacetyl chlorides: Synthesis of 2a,3,4,5‐tetrahydro‐azeto [1,2‐a][1,5] benzodiazepin‐1(2H)‐ones
Authors: Xu Jiaxi , Zuo Gang , Chan Wing Lai
Published: August 2002

2a,4‐Disubstituted 5‐benzoyl‐2‐chloro/2,2‐dichloro‐2a,3,4,5‐tetrahydro‐azeto [1,2‐a] [1,5]benzodiazepin‐1 (2H)‐ones (3a–h) were synthesized by cycloaddition reactions of 2,4‐disubstituted 1‐benzoyl‐2,3‐dihydr o‐1H‐1,5‐benzodiazepines (2a–h) and ketenes, generated from chloroacetyl chloride or dichloroacetyl chloride in the presence of triethylamine, in anhydrous benzene. In some cases, ring contraction of benzodiazepines has also been observed. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:636–640, 2001
Solving the surgical waiting list problem? New Zealand's ‘booking system’
Authors: Gauld Robin , Derrett Sarah
Published: August 2002

This article discusses the development and implementation of New Zealand's booking system for publicly funded non‐urgent surgical and medical procedures. The ‘booking system’ emerged out of New Zealand's core services debate and the government's desire to remove waiting lists. It was targeted for implementation by mid‐1998. However, the booking system remains in an unsatisfactory state and a variety of problems have plagued its introduction. These include a lack of national consistency in the priority access criteria, failure to pilot the system and a shortfall in the levels of funding available to treat the numbers of patients whose priority criteria ‘scores’ deem them clinically eligible for surgery. The article discusses endeavours to address these problems. In conclusion, based on the New Zealand experience, the article provides lessons for policy‐makers interested in introducing surgical booking systems. Copyright © 2000 John Wiley & Sons, Ltd.
Pool boiling heat transfer in binary mixtures of ammonia/water: Effect of heat of dilution and dissolution on heat transfer coefficient
Authors: Inoue Toshiaki , Monde Masanori , Teruya Yoshio , Ikeda Hideki
Published: August 2002

Nucleate boiling heat transfer coefficients were measured on a horizontal heated wire during the pool boiling of non‐azeotropic mixtures of ammonia/water. The experiment was carried out at pressures of 0.4 and 0.7 MPa, at heat fluxes below 2.0 × 106 W/m2, and over a range of mass fraction. The heat transfer coefficients in the mixtures were smaller than those in single‐component substances. No existing correlation is found to predict boiling heat transfer coefficients over the range of mass fraction of interest. In the mixtures of the ammonia/water, the heats of dilution and dissolution were generated near a liquid surface while vapor with a rich concentration of ammonia was condensed and then was diffused into the bulk liquid; while in most other mixtures, little heat was generated during any dilution and dissolution. In relation to the heat generated, the effect of the heats of dilution and dissolution on pressure and temperature in a system (pressure vessel) is shown herein. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(4): 272–283, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10034
Numerical simulation of natural convection heat transfer in the open space between two horizontal circular planes
Authors: Tokanai Hideki , Shishido Masahiro , Kuriyama Masafumi , Konno Hirotaka
Published: August 2002

Numerical simulations were conducted for natural convection heat transfer in a narrow gap between two horizontal plates in air. The lower plate is an infinite plate with a circular heating zone. The upper one is the bottom of a vertical cylinder, which is placed right above the circular heated plate and kept at room temperature.

A set of Navier–Stokes equations and an energy equation are analyzed for a variety of combinations of gap clearance and Rayleigh number. The calculated average heat transfer values are shown to be in good agreement with the experimentally obtained ones reported in a previous paper. From the obtained isotherms, streamlines, and local Nusselt numbers, it is found that two types of convection appear in the gap space according to the conditions of Rayleigh number and gap clearance: one is a simple convection due to a single renewal flow which replaces heated air with ambient air and the other is a combined convection due to several vortex flows and a renewal flow. Furthermore, the flow rate of each flow controls the rate of heat transfer from the limited area which is covered by each flow. From this fact, the validity of the previously proposed heat transfer correlation is briefly discussed. © 2001 Scripta Technica, Heat Trans Asian Res, 30(6): 485–502, 2001
Modelling of groundwater mound formation resulting from transient recharge
Authors: Rai S. N. , Ramana D. V. , Thiagarajan S. , Manglik A.
Published: August 2002

An analytical solution of a linearized Boussinesq equation is obtained to predict water table fluctuations as a result of time varying recharge from a strip basin for any number of recharge cycles. The analytical solution is obtained by using finite Fourier sine transform. Applications of the solution for the prediction of water table fluctuations and sensitivity analysis are demonstrated with the help of example problems. Copyright © 2001 John Wiley & Sons, Ltd.
Persistant human papillomavirus infection and smoking increase risk of failure of treatment of cervical intraepithelial neoplasia (CIN)
Authors: Acladious Nabil Nathan , Sutton Chrostopher , Mandal Debbi , Hopkins Rami , Zaklama Magid , Kitchener Henery
Published: August 2002

Women with abnormal smears have an increased risk of developing cervical cancer. During the 8 years following conservative treatment of cervical intraepithelial neoplasia (CIN), their risk of invasive cervical cancer is about 5 times greater than that of the general population. Human papillomavirus (HPV) has been associated with the natural history of both CIN and cervical cancer. To date, there have been no published reports on the predictive value of HPV testing in the treatment outcome of CIN. A prospective, multi‐center, cohort study was conducted on women in the Northwest of England who were attending for treatment of CIN. They were asked to complete a questionnaire, which included a detailed smoking history. Pre‐ and post‐treatment HPV testing was performed on cervical biopsies and cervical swab, being taken with the first follow‐up smear at 6 months. A nested case‐control analysis was performed, cases being defined as women who developed CIN within the 2 years of treatment and controls being sampled from those who did not experience treatment failure within 2 years. Multiple conditional logistic regression is used to study the factors associated with treatment failure of CIN. The cohort included 958 women of whom 77 (8%) experienced treatment failure (cases). Two controls were matched to each case (154). Smoking status was significantly associated with CIN treatment failure(p= 0.0013). Current smokers had a 3‐fold increased risk of treatment failure of CIN as compared to non‐smokers (95% CI 1.65 to 5.91). Five hundred twenty‐five women underwent HPV sampling following treatment, of whom 47 (8.9%) developed further CIN. Post‐treatment positive HPV testing was found to be strongly associated with treatment failure of CIN (OR 23.3; 95% CI 3.15–172.1). In 11/45 cases with negative smear at first follow‐up, the HPV test was positive. The combination of both HPV and cytology in the first follow‐up visit predicted treatment failure in 72% of the cases. Cigarette smoking is a factor, which, independently of HPV infection, influences the treatment outcome of CIN. Smokers and those who are HPV positive during follow‐up appear to require longer, more intensive follow‐up. HPV testing requires careful consideration as part of routine follow‐up protocol following treatment of CIN. © 2002 Wiley‐Liss, Inc.
The effect of different soothing interventions on infant crying and on parent–infant interaction
Authors: Elliott M. Ruth , Reilly Sandra M. , Drummond Jane , Letourneau Nicole
Published: August 2002

Conducted in the home environment, this study examines the effects of three complementary soothing techniques on the duration of infant crying and on caregiver–infant interaction. In one group, the caregivers apply massage; in another, they provide supplemental carrying to their infants, and in the last, the caregivers both massage and provide supplemental carrying. Measurements, for the one control and three treatment groups took place prenatally (third trimester) and in the first 16 weeks postpartum for parental perception of infant temperament, parental sense of competence, parent–infant interaction, and the duration of infant crying. Whereas analyses indicate no statistically significant differences between groups in reducing infant crying, results approached significance (p ≤ .06) in favor of the combined supplemental carrying/massage group. These results challenge accepted beliefs that tactile stimulation and/or supplemental carrying enhance parental sense of competence, positive parental perceptions, and interactions with infants. Practitioners can apply these conclusions when counselling parents on the advisability of selecting any one complementary soothing technique. ©2002 Michigan Association for Infant Mental Health.
Customer Relationship Management
Authors: Fayerman Michael
Published: August 2002

This chapter presents an approach increasingly employed by businesses to track and respond to their customers to provide better and faster services. It discusses the applicability of customer relationship management to the operations of higher education and institutional research and the role it plays in the knowledge management framework.
Cancer risk assessment for oral exposure to PAH mixtures
Authors: Schneider K. , Roller M. , Kalberlah F. , Schuhmacher‐Wolz U.
Published: August 2002

Cancer risk estimates for oral uptake of polycyclic aromatic hydrocarbons (PAHs) currently are based on risk estimates for benzo[a]pyrene (BAP). The potency of PAH mixtures often is calculated using relative potency values (BAP equivalency factors). We used recent oral carcinogenicity studies with BAP and coal tar mixtures, as well as older studies for a critical reappraisal of the current practice. A literature survey identified several carcinogenicity studies with oral and dermal exposure and lung implantation that allow a direct comparison of the carcinogenic potency of pure BAP and PAH mixtures. Moreover, when the PAH composition of the mixture has been analysed, prediction of the potency of PAH mixtures by BAP equivalency factors could be compared with the observed PAH potency. The analysis indicates that BAP equivalency factors do not describe adequately the potency of PAH mixtures and lead to underestimations of carcinogenic potency in most cases. Evaluation of several studies with various PAH mixtures revealed that the potency ratio between pure BAP and the PAH mixture in the same assay is highly dependent on the exposure pathway and the target organ, therefore potency estimates for PAH mixtures should be derived separately for oral, dermal and inhalative exposure using data from studies with the relevant pathway. A cancer slope factor for oral PAH exposure was derived based on data from a recent feeding study with coal tar mixtures. By using incidence data for all exposure‐related tumours, a slope factor for humans of 11.5 (human excess risk per oral lifetime exposure with 1 mg BAP kg−1day−1 in a PAH mixture) was obtained. Our analysis led to the conclusion that the contribution of BAP to the carcinogenic potency of the mixture depends on the exposure pathway and type of cancer observed but is relatively constant for various PAH mixtures from industrial sources. Thus, the derived oral slope factor is recommended to be used for the risk assessment of PAH‐contaminated soils. Copyright © 2002 John Wiley & Sons, Ltd.
In vitro behavior of albumin‐loaded carbonate hydroxyapatite gel
Authors: Barralet J. E. , Aldred S. , Wright A. J. , Coombes A. G. A.
Published: August 2002

Hydroxyapatite (HA) powder, porous HA, plasma‐sprayed HA, apatite cements, and sintered HA have all been investigated as delivery systems for compounds such as human growth hormone and vancomycin. However, many previous studies showed that the period of release was limited to 2–3 weeks. The concept of using a nanoporous matrix as a means of immobilizing proteins is well known but has largely been confined to silica‐based systems. Carbonate hydroxyapatite (CHA) is more soluble in vivo than HA, and when formed as an aqueous precipitate, it is often formed as nanocrystals. This study investigated the release profiles of ovine albumin (OVA) from CHA gel stored in phosphate‐buffered saline (PBS) and double distilled water (DDW) for times of up to 1 year. It was found that 7.9% OVA could be loaded onto apatitic gels by means of a purely aqueous process. This process provided a simple low‐temperature method of protein adsorption on a high surface area apatitic matrix at physiological pH. The rate of short‐term release of OVA was lower from CHA gels than from microcrystalline HA powder. However, the period of release from the CHA gel was short term and may have been associated with recrystallization of the gel. OVA loaded into CHA gel was found to remain undegraded in vitro at 37°C for periods of up to 1 year. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 360–367, 2002; DOI 10.1002/jbm.10070
Sequential robust design methodology and X‐ray photoelectron spectroscopy to analyze the grafting of hyaluronic acid to glass substrates
Authors: Stile Ranee A. , Barber Thomas A. , Castner David G. , Healy Kevin E.
Published: August 2002

Sequential Robust Design experiments and X‐ray photoelectron spectroscopic (XPS) studies were performed to examine the immobilization of hyaluronic acid (HA) on glass substrates chemisorbed with N‐(2‐aminoethyl)‐3‐aminopropyl‐trimethoxysilane (EDS). Numerous reaction conditions were investigated, including the concentrations of 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride (EDC), N‐hydroxysulfosuccinimide (Sulfo‐NHS), and HA, and the reaction buffer type, concentration, and pH. The elemental surface compositions of carbon and silicon (C/Si ratio) were used to assess the extent of HA immobilization, leading to the identification of critical HA‐binding reaction conditions and the determination of an optimum surface chemistry. The optimum chemistry consisted of 200 mM EDC, 50 mM Sulfo‐NHS, 10 mM N‐(2‐hydroxyethyl)piperazine‐N′‐(2‐ethanesulfonic acid) (HEPES) buffer at a pH of 7.0, and 3 mg/mL HA. This work emphasizes the advantages of using Robust Design methods over traditional statistical experimental design, particularly when large numbers of variables are examined and costly analytical techniques are employed. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 391–398, 2002
Alteration of leukocyte motility on plasma‐conditioned prosthetic biomaterial, ePTFE, via a flow‐responsive cell adhesion molecule, CD43
Authors: Rosenson‐Schloss Rene S. , Chang Charlie C. , Constantinides Alkis , Moghe Prabhas V.
Published: August 2002

The physiologic determinants of leukocyte migration on vascular prosthetic biomaterials remain poorly understood, despite their relevance to the control of periprosthetic infection. Using hemodynamic exposure of human polymorphonuclear leukocytes adherent to expanded polytetrafluoroethylene (ePTFE) in vitro, we investigated the role of fluid shear in regulating leukocyte migratory behavior on plasma‐adsorbed, prosthetic vascular biomaterial. The presence of flow at a wall shear stress of 25 dyn/cm2 increased the degree of leukocyte displacement along the flow direction without altering the degree of overall cell attachment. Moreover, plasma‐ePTFE elicited a lower overall degree of displacement under flow in comparison with untreated ePTFE. We further probed the molecular level regulation of leukocyte migratory responses under flow through the immunocytochemical quantification of specific leukocyte adhesion molecules and determined that CD43, a cell adhesion molecule, was upregulated via flow exposure for leukocytes adherent to plasma‐ePTFE, whereas basal levels of CD43 expression were not significantly altered on untreated ePTFE. When flow‐exposed, adherent leukocytes were incubated in the presence of substrate immobilized anti‐CD43 immunoglobulin, the degree of cell displacement along flow was found to be significantly enhanced on plasma‐ePTFE. Quantification of the cell population redistribution under flow using a modified random motility model, indicated that the incorporation of anti‐CD43 on plasma‐ePTFE led to a significant increase (243 ± 60%) in the cell dispersion coefficient, μD, whereas only a minimal increase (61 ± 30%) was detected on non‐adsorbed ePTFE. Overall, our results suggest that flow exposure can induce the migration of leukocytes adherent to prosthetic materials in a substrate‐dependent manner. An important implication of our study is that, although biomaterials exposed to plasma intrinsically passivate leukocyte migration even under hemodynamic conditions, it may be possible to promote cell motility by targeting a specific, flow‐responsive, adhesion molecule. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 8–19, 2002
Acute sodium arsenite administration induces pulmonary CYP1A1 mRNA, protein and activity in the rat
Authors: Seubert John M. , Sinal Christopher J. , Bend John R.
Published: August 2002

Modulation of the cytochrome P450 (CYP) monooxygenase system (P450) by arsenite was investigated in male, adult Sprague‐Dawley rats treated with a single dose (75 μmol/kg, sc) of sodium arsenite (As3+). Total CYP content and P450‐dependent 7‐pentoxyresorufin O‐pentylation (PROD) and 7‐ethoxyresorufin O‐deethylation (EROD) activities of liver microsomes decreased maximally (33, 35, and 50% of control, respectively) 1 day after As3+ treatment. Maximum decreases of CYP content and P450 catalytic activities corresponded with maximum increases of microsomal heme oxygenase (HO) activity and with increased total plasma bilirubin concentrations. EROD activity increased maximally in lung (300%) 5 days after a single dose of As3+. Lung CYP1A1 mRNA and protein levels also increased maximally 5 days after treatment. A small but significant increase in EROD activity (65%) was observed in lung microsomes 24 h following a 1 h infusion of bilirubin (7.5 mg/kg) into rats. However, administration of bilirubin to the lung via intratracheal injection (0.25 and 2.5 mg/kg) did not increase CYP1A1 monooxygenase activity or mRNA. This study demonstrates that P450 is modulated in an isozyme (CYP1A1 vs CYP2B1/2) selective manner in rat lung after acute As3+ administration. Administration of bilirubin, a potential aryl hydrocarbon receptor (AHR) ligand, by infusion or intratracheal instillation did not upregulate pulmonary CYP1A1 at the mRNA level under our treatment conditions. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:84–95, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/jbt.10022
Changes in the levels of glutathione after cellular and cutaneous damage induced by squalene monohydroperoxide
Authors: Chiba Katsuyoshi , Yoshizawa Kazuhiko , Makino Ikuyo , Kawakami Koji , Onoue Masaharu
Published: August 2002

Squalene monohydroperoxide (Sq‐OOH), the initial product of ultraviolet‐peroxidated squalene, was used to investigate the effect of peroxidative challenge upon the glutathione contents in rabbit ear skin and primary‐cultured fibroblasts derived from rabbit ear skin. The cellular reduced glutathione (GSH) contents decreased during 30‐minute incubations in vitro with Sq‐OOH, and oxidized glutathione (GSSG) was formed concomitantly, indicating that Sq‐OOH had a potential for GSH‐depleting activity in vitro. When Sq‐OOH was applied topically to the skin in vivo, only GSSG contents increased significantly within 30 minutes. Moreover, pretreatment with the GSH depletors, DL‐buthionine sulfoximine (BSO) and diethyl maleate (DEM), could potentiate the cytotoxicity and comedogenicity induced by Sq‐OOH. These findings suggest that the endogenous antioxidant, glutathione, is quite sensitive to Sq‐OOH and may be an important material for protecting cells and/or tissues against the oxidative stress induced by Sq‐OOH treatment. © 2001 John Wiley & Sons, Inc. J Biochem Mol Toxicol 15:150–158, 2001
Nitroxide TEMPOL impairs mitochondrial function and induces apoptosis in HL60 cells
Authors: Monti Elena , Supino Rosanna , Colleoni Mariapia , Costa Barbara , Ravizza Raffaella , Gariboldi Marzia B.
Published: August 2002

The piperidine nitroxide TEMPOL induces apoptosis in a number of tumor cell lines through free radical‐dependent mechanisms. As mitochondria play a major role in apoptosis as both source and target for free radicals, the present study focuses on mitochondrial effects of TEMPOL in a human promyelocytic leukemic cell line (HL‐60). On 24‐h exposure to TEMPOL, the following alterations were observed: 1) decrease in both the intracellular and mitochondrial glutathione pools; 2) impairment of oxidative phosphorylation; and 3) decrease in mitochondrial membrane potential. In addition, TEMPOL was found to specifically target complex I of the respiratory chain, with minor effects on complexes II and IV, suggesting that mitochondrial effects might play a role in TEMPOL‐induced oxidative stress and apoptosis, and that TEMPOL might sensitize tumor cells to the pro‐apoptotic effects of cytotoxic agents. J. Cell. Biochem. 82: 271–276, 2001. © 2001 Wiley‐Liss, Inc.
Response of bovine endothelial cells to FGF‐2 and VEGF is dependent on their site of origin: Relevance to the regulation of angiogenesis
Authors: Cavallaro Ugo , Tenan Mirna , Castelli Vera , Perilli Alessandra , Maggiano Nicola , Van Meir Erwin G. , Montesano Roberto , Soria Marco R. , Pepper Michael S.
Published: August 2002

Angiogenesis, the formation of new capillary blood vessels, occurs almost exclusively in the microcirculation. This process is controlled by the interaction between factors with positive and negative regulatory activity. In this study, we have compared the effect of two well described positive regulators, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF‐2) on bovine adrenal cortex‐derived microvascular endothelial (BME) and bovine aortic endothelial (BAE) cells. The parameters we assessed included (a) cellular reorganization and lumen formation following exposure of the apical cell surface to a three‐dimensional collagen gel; (b) organization of the actin cytoskeleton; (c) expression of thrombospondin‐1 (TSP‐1), an endogenous negative regulator of angiogenesis; and (d) extracellular proteolytic activity mediated by the plasminogen activator (PA)/plasmin system. We found that (a) collagen gel overlay induces rapid reorganization and lumen formation in BME but not BAE cells; (b) FGF‐2 but not VEGF induced dramatic reorganization of actin microfilaments in BME cells, with neither cytokine affecting BAE cells; (c) FGF‐2 decreased TSP‐1 protein and mRNA expression in BME cells, an effect which was specific for FGF‐2 and BME cells, since TSP‐1 protein levels were unaffected by VEGF in BME cells, or by FGF‐2 or VEGF in BAE cells; (d) FGF‐2 induced urokinase‐type PA (uPA) in BME and BAE cells, while VEGF induced uPA and tissue‐type PA in BME cells with no effect on BAE cells. Taken together, these findings reveal endothelial cell‐type specific responses to FGF‐2 and VEGF, and point to the greater specificity of these cytokines for endothelial cells of the microvasculature than for large vessel (aortic) endothelial cells. Furthermore, when viewed in the context of our previous observation on the synergistic interaction between VEGF and FGF‐2, our present findings provide evidence for complementary mechanisms which, when acting in concert, might account for the synergistic effect. J. Cell. Biochem. 82: 619–633, 2001. © 2001 Wiley‐Liss, Inc.
Critical amino acid residues of the α4 subunit for α4β7 integrin function
Authors: Zeller Yvonka , Mechtersheimer Sabine , Altevogt Peter
Published: August 2002

A characteristic feature of integrin–ligand interactions is the requirement for divalent cations. Putative cation binding sites have been identified in the α and β subunit of the α4 integrins, α4β1 and α4β7, and within their ligands which display the tripeptide LDV in fibronectin and homologous motifs in VCAM‐1 and MAdCAM‐1. The extracellular domain of the murine and human α4‐subunit contains three conserved LDV motifs, designated LDV‐1 to ‐3. Using site directed mutagenesis and transfection studies, we now examined the functional relevance of the LDV motifs for α4β7 integrins. We present evidence that LDV‐1 mutants (D489N) behave like α4 wt cells, but LDV‐3 mutants (D811N) are impaired in α4β7 integrin‐triggered homotypic cell aggregation and in adhesion and spreading on α4 specific ligands. Further characterization of LDV‐3 mutants revealed a defect in mAb‐induced α4β7‐cell surface cluster formation. Mutation of the LDV‐2 motif (D698N) caused loss of α4β7 integrin cell surface expression. Our results indicate: (i) that LDV‐3, located proximal to the cell membrane, is important for α4β7 integrin‐triggered functions and for lateral clustering and (ii) that LDV‐2 affects α4β7 heterodimer stability. J. Cell. Biochem. 83: 304–319, 2001. © 2001 Wiley‐Liss, Inc.
Conformational analysis of the tyrosine dipeptide analogue in the gas phase and in aqueous solution by a density functional/continuum solvent model
Authors: Langella Emma , Rega Nadia , Improta Roberto , Crescenzi Orlando , Barone Vincenzo
Published: August 2002

The conformational behavior of a dipeptide analogue of tyrosine (TDA) has been investigated by density functional methods using the polarizable continuum model (PCM) for the description of solvent effects. Our study points out the interplay of backbone and side chain contributions in determining the relative stabilities of energy minima. In particular, stabilizing interactions between the NH bond and the aromatic ring have a significant effect. The topology of the potential energy surface is significantly modified in aqueous solution due to a general widening of low energy regions and to a stabilization of helical structures. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 650–661, 2002
Applicability of MNDO techniques AM1 and PM3 to ring‐structured polymers
Authors: Dávila L. Y. A. , Caldas M. J.
Published: August 2002

Semiempirical Hartree‐Fock techniques are widely used to study properties of long ring‐structured chains, although these types of systems were not included in the original parametrization ensembles. These techniques are very useful for an ample class of studies, and their predictive power should be tested. We present here a study of the applicability of some techniques from the NDDO family (MNDO, AM1, and PM3) to the calculation of the ground state geometries of a specific set of molecules with the ring‐structure characteristic. For this we have chosen to compare results against ab initio Restricted Hartree‐Fock 6‐31G(d,p) calculations, extended to Møller‐Plesset 2 perturbation theory for special cases. The systems investigated comprise the orthobenzoquinone (O2C6H4) molecule and dimers (O2C6H4)2, as well as trimers of polyaniline, which present characteristics that extend to several systems of interest in the field of conducting polymers, such as ring structure and heterosubstitution. We focus on the torsion between rings, because this angle is known to affect strongly the electronic and optical properties of conjugated polymers. We find that AM1 is always in qualitative agreement with the ab initio results, and is thus indicated for further studies of longer, more complicated chains. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1135–1142, 2002
Structure‐based ligand design by a build‐up approach and genetic algorithm search in conformational space
Authors: Budin Nicolas , Majeux Nicolas , Tenette–Souaille Catherine , Caflisch Amedeo
Published: August 2002

Program to engineer peptides (PEP) is a build‐up approach for ligand docking and design with implicit solvation. It requires the knowledge of a seed from which it iteratively grows polymeric ligands consisting of any type of amino acid, i.e., natural and/or nonnatural from a user‐defined library. At every growing step, a genetic algorithm is used for conformational optimization of the last added monomer in the rigid binding site. Pruning is performed at every growing step by selecting sequences according to binding energy with electrostatic solvation. PEP is applied to three members of the caspase family of cysteine proteases using Asp at P1 as seed. The optimal P4–P2 peptide recognition motifs and variants thereof are docked correctly in the active site (backbone root‐mean‐square deviation < 0.9 Å). Moreover, for each caspase, the P4–P2 sequences of potent aldehyde inhibitors are ranked among the 15 hits with the most favorable PEP energy. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1956–1970, 2001
Folding funnels: The key to robust protein structure prediction
Authors: Hardin Corey , Eastwood Michael P. , Prentiss Michael , Luthey‐Schulten Z. , Wolynes Peter G.
Published: August 2002

Natural proteins fold because their free energy landscapes are funneled to their native states. The degree to which a model energy function for protein structure prediction can avoid the multiple minima problem and reliably yield at least low‐resolution predictions is also dependent on the topography of the energy landscape. We show that the degree of funneling can be quantitatively expressed in terms of a few averaged properties of the landscape. This allows us to optimize simplified energy functions for protein structure prediction even in the absence of homology information. Here we outline the optimization procedure in the context of associative memory energy functions originally introduced for tertiary structure recognition and demonstrate that even partially funneled landscapes lead to qualitatively correct, low‐resolution predictions. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 138–146, 2002
MMPI‐2 performance of Mexican male university students and prison inmates
Authors: Boscan Deisy C. , Penn Nolan E. , Velasquez Roberto J. , Savino Aimee V. , Maness Paula , Guzman Miguel , Reimann Joe
Published: August 2002

In this study, we compared the Minnesota Multiphasic Personality Inventory—2 (MMPI‐2) performance of male university students and incarcerated criminal offenders in Mexico. Our aim was to determine whether the MMPI‐2 can effectively differentiate between these two distinct groups on scales that are reflective of antisocial behaviors. Our expectations were highly confirmed across the three sets of scales that we considered: the validity and clinical, content, and supplementary scales. Criminal offenders obtained higher or more pathological scores on such scales as Infrequency (F), Schizophrenia (Sc), MacAndrew Alcoholism Scale (MAC‐R), Fears (FRS), and so on. Overall, these findings support further research with such target populations as prison inmates in Mexico and other countries in Latin America. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 465–470, 2002.