bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexural strength distribution of a PMMA‐based bone cement
Authors: Vallo Claudia I.
Published: October 2004

Polymethylmethacrylate bone cement containing either no added antibiotic or 0.5 g of Gentamicin was prepared and stored either in air at room temperature or in a 37 °C water bath for 48 h. An additive‐free cement stored in air at room temperature was also tested for purposes of comparison. Following storage the specimens were tested in flexure. Weibull statistics demonstrated to fit the flexural strength distribution of all the materials tested with regression coefficients of at least 0.98. The presence of a BaSO4 radiopacifier markedly reduced the mean flexural strength and increased the data scatter in the air‐stored specimens. On the other hand, the flexural strength of both impregnated and nonimpregnated antibiotic increased when those materials were stored in water at 37 °C, compared with the same material stored in air, as a consequence of the water ingress. The water‐stored antibiotic‐impregnated cement displayed lower flexural strength, increased data scatter, and a remarkably higher number of weak specimens compared with the antibiotic‐free cement. The influence of the load type on the flexural behavior was studied by testing the air‐stored specimens in three‐point bending and four‐point bending. Cements tested in four‐point bending resulted in lower flexural strength than that tested in three‐point bending. The ratio of mean strength measured in the different load arrangements was satisfactory, as predicted by the Weibull model. © 2002 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 63: 226–236, 2002; DOI 10.1002/jbm.10129
A new electrochemically graded hydroxyapatite coating for osteosynthetic implants promotes implant osteointegration in a rat model
Authors: Schmidmaier G. , Wildemann B. , Schwabe P. , Stange R. , Hoffmann J. , Südkamp N. P. , Haas N. P. , Raschke M.
Published: October 2004

Hydroxyapatite (HAP) is widely used as an osteoconductive coating for orthopedic implants. So far standard coating methods like plasma spraying produce a relatively thick coating layer (>30 μm). In addition, the chemical structure of the HAP may be altered because of the heating throughout the coating process. This may have negative effects on the coating stability, implant fixation, and induction of bone formation. The relatively thick layer may detach from the implant with the risk of wear debris. In the present study the potential of a newly developed HAP coating of implants on osteointegration was investigated in a rat model. The coating method, based on an electrochemical process, is applied in a graded manner and results in a biodegradable HAP coating with a thickness of approximately 2 μm. Coated versus uncoated titanium Kirschner wires (1.4‐mm diameter) were inserted into the medullary cavity of the right femora of 5‐month old female Sprague Dawley rats (n=36) in a retrograde fashion. Throughout an experimental period of 2 months the osteointegration was traced radiologically. After this time the animals were sacrificed and the implant integration was tested biomechanically with the use of a push‐out test. To analyze the bone‐implant interface, histological sections (80 μm) were investigated with an image analyzing system. The biomechanical testing revealed a significantly higher implant fixation in the group treated with the HAP‐coated implant (shear strength: 27.8 ± 6.7 MPa) compared to control (shear strength: 8.08 ± 3.4 MPa). The histological analyses demonstrated a better ingrowth of the implants in the HAP group with significantly more direct bone‐implant contacts compared to the control group. The results demonstrate that the HAP coating promotes implant osteointegration in a rat model. © John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 63: 168–172, 2002; DOI 10.002/jbm.10130
Bioactive glass as bone‐graft substitute for posterior spinal fusion in rabbit
Authors: Lindfors N. C. , Tallroth K. , Aho A. J.
Published: October 2004

Bioactive glass S53P4 and autogenous bone were studied as bone graft materials for spinal fusion in a rabbit model. Sixteen rabbits underwent surgery by a dorsal approach. A bioactive glass, a combination of bioactive glass and autogenous bone (70/30 vol%), and autogenous bone were implanted at two thoracolumbar vertebraes for 4 and 12 weeks. The volume, consolidation to vertebrae, and fusion of the graft material were evaluated with plain‐film radiology, computed tomography (CT) and bone‐mineral density measurements, and compared with histomorphometrical measurements. Radiological consolidation by CT of bone graft to underlying vertebrae at 12 weeks was observable in all groups. This was histologically confirmed as bone was growing from the vertebrae into the graft material. Radiologic fusion of vertebraes was, at 12 weeks, observable in all groups in 50–75% of the cases. The radiologic fusion seen at the CT scans could, however, not be confirmed by histology in any of the three groups. Significant differences for graft material and observation period with the use of bone‐mineral density measurements (Hounsfield units) were also observable, with the highest measured values for the bioactive glass group and the lowest for the autogenous bone group. The results indicate that bioactive glass have potential as bone‐graft material in spinal fusion. The reliability of radiologic evaluation methods in spinal surgery using bone substitutes is also questioned and discussed. © 2002 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 63: 237–244, 2002; DOI 10.1002/jbm.10177
Failure characteristics of multiple‐component fibrin‐based adhesives
Authors: Sierra David H. , Eberhardt Alan W. , Lemons Jack E.
Published: October 2004

A series of analyses were performed on fibrin‐based adhesives to describe their failure characteristics. Two test methods were used: uniaxial, monotonic tensile testing of the bulk material, and blister testing using fresh porcine‐source skin graft as the adherend. Two fibrin concentrations, high (HFC), and low (LFC), were used to investigate the effects of the gel matrix density upon mechanical properties. In tensile tests, fibrin gels strain hardened, as functions of percent strain and of strain rate. An increase in modulus of elasticity (E) was seen with increasing strain and strain rate at both tested fibrin concentrations. Mode I failure mechanisms were predominant. Both adhesives appeared to fracture from the outer edge to the interior of the specimen at slower strain rate tests. This trend reversed as strain rate increased, becoming a classic “cup and cone” ductile fracture. Syneresis occurred at both concentrations at lower strain rates, but was more pronounced for the LFC. Ultimate tensile strength and E were greater for the HFC than for the LFC at all strain rates, decreasing with increasing strain rate. In the blister test, the failure locus changed from cohesive to adhesive as the strain rate was increased for the HFC. Failure of fibrin gels likely occurs by percolation of the pressurized saline, displacing the entrapped liquid phase of the gel in regions of relatively low moduli and strength, leading to fracture of the matrix. For LFC, the overall fracture locus remained predominantly cohesive regardless of strain rate. Burst strength and failure energy were higher for HFC than for LFC. It would appear that fibrin acts more as a viscous liquid than a rubberlike/elastic material at lower concentrations because adhesive failures had a higher burst strength and fracture energy (Gc) than did cohesive failures. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 1–11, 2002
Implanted octacalcium phosphate is more resorbable than β‐tricalcium phosphate and hydroxyapatite
Authors: Kamakura S. , Sasano Y. , Shimizu T. , Hatori K. , Suzuki O. , Kagayama M. , Motegi K.
Published: October 2004

Our previous studies have suggested that synthetic octacalcium phosphate (OCP) could be resorbed and replaced by newly formed bone if implanted in rat skull defects. We hypothesized that the implanted OCP is more resorbable than other commonly used bone graft substitutes of calcium phosphate compounds, such as hydroxyapatite (HA) and β‐tricalcium phosphate (β‐TCP). To test the hypothesis, the present study was designed to compare histomorphometrically resorption of the implanted OCP, HA, and β‐TCP, which were kept in the experimental cranial defect of rats for a long term. A full thickness of standardized trephine defect was made in the rat parietal bone, and the same volume of granules of OCP, HA, and β‐TCP were implanted into the defect. Five specimens of each group were fixed 6 months after implantation. The percentage of remaining implants (r‐Imp%) and newly formed bone (n‐Bone%) in the defect was analyzed histomorphometrically. The statistical analysis showed that the r‐Imp% of OCP was significantly lower than that of HA and β‐TCP. In contrast, the n‐Bone% of OCP was significantly higher than that of HA and β‐TCP. The present study has shown that the implanted OCP in the rat cranial defect is more resorbable than the implanted β‐TCP and HA, whereas the implanted OCP enhances bone formation more than the implanted β‐TCP and HA. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 29–34, 2002
Assessment of the genotoxicity of resin and zinc‐oxide eugenol‐based root canal sealers using an in vitro mammalian test system
Authors: Tai Kuo‐Wei , Huang Fu‐Mei , Huang Min‐Sheng , Chang Yu‐Chao
Published: October 2004

Endodontic sealers frequently are placed in direct contact with living tissues. Thus root canal sealers should have good biocompatibility. However, the pathobiologic effects, especially genotoxicity, of various root canal sealers widely used in dentistry have not been studied systematically on eukaryotic cells. The aim of this study was to examine the genotoxic potential of resin and zinc oxide–eugenol‐based root canal sealers using a mammalian test system. In this study, tetrazolium bromide reduction assay, DNA precipitation assay, and DNA fragmentation analysis were performed to investigate the cytotoxic and genotoxic effects of four different root canal sealers on cultured V79 cells. The results show that all the root canal sealers tested are cytotoxic to V79 cells. The toxicity decreased in the order of N2 > AH26 > AHplus > Canals. In addition, N2, AH26, and AHplus exhibited genotoxicity by causing DNA single‐strand breaks and digestion of genomic DNA. However, N2 is the most toxic root canal sealer among those tested. Taken together, these findings suggest that the sealers evaluated in this study show different toxic effects depending on the types and components. Root canal sealers containing formaldehyde and bisphenol A diglyether proved to be not only cytotoxic but also genotoxic. This mammalian test system might be used routinely for evaluation of the genotoxicity of dental materials in future investigations. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 73–77, 2002
In vitro stability of a novel compliant poly(carbonate‐urea)urethane to oxidative and hydrolytic stress
Authors: Salacinski Henryk J. , Tai Nigel R. , Carson Robert J. , Edwards Alan , Hamilton George , Seifalian Alexander M.
Published: October 2004

Poly(ester)urethane and poly(ether)urethane vascular grafts fail in vivo because of hydrolytic and oxidative degradative mechanisms. Studies have shown that poly(carbonate)urethanes have enhanced resistance. There is still a need for a viable, nonrigid, small‐diameter, synthetic vascular graft. In this study, we sought to confirm this by exposing a novel formulation of compliant poly(carbonate‐urea)urethane (CPU) manufactured by an innovative process, resulting in a stress‐free. Small‐diameter prosthesis, and a conventional poly(ether)urethane Pulse‐Tec graft known to readily undergo oxidation in a variety of degradative solutions, and we assessed them for the development of oxidative and hydrolytic degradation, changes in elastic properties, and chemical stability. To simulate the in vivo environment, we used buffered solutions of phospholipase A2 and cholesterol esterase; solutions of H2O2/CoCl2, t‐butyl peroxide/CoCl2 (t‐but/CoCl2), and glutathione/t‐butyl peroxide/CoCl2 (Glut/t‐but/CoCl2); and plasma fractions I–IV, which were derived from fresh human plasma centrifuged in poly(ethylene glycol). To act as a negative control, both graft types were incubated in distilled water. Samples of both graft types (100 mm with a 5.0‐mm inner diameter) were incubated in these solutions at 37°C for 70 days before environmental scanning electron microscopy, radial tensile strength and quality control, gel permeation chromatography, and in vitro compliance assessments were performed. Oxidative degradation was ascertained from significant changes in molecular weight with respect to a control on all Pulse‐Tec grafts treated with t‐but/CoCl2, Glut/t‐but/CoCl2, and plasma fractions I–III. Pulse‐Tec grafts exposed to the H2O2/CoCl2 mixture had significantly greater compliance than controls incubated in distilled water (p < 0.001 at 50 mmHg). No changes in molecular weight with respect to the control were observed for the CPU samples; only those immersed in t‐but/CoCl2 and Glut/t‐but/CoCl2 showed an 11% increase in molecular weight to 108,000. Only CPU grafts treated with the Glut/t‐but/CoCl2 mixture exhibited significantly greater compliance (p < 0.05 at 50 mmHg). Overall, results from this study indicate that CPU presents a far greater chemical stability than poly(ether)‐urethane grafts do. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 207–218, 2002
Nucleation and growth of hydroxyapatite on an amino organosilane overlayer
Authors: Zhu P. X. , Ishikawa M. , Seo W. S. , Hozumi A. , Yokogawa Y. , Koumoto K.
Published: October 2004

An amino organosilane overlayer (NH2‐overlayer) was successfully processed on Si/SiO2 substrates. Remarkable nucleation and growth of hydroxyapatite were found to take place on an NH2‐overlayer after Si/SiO2 substrates covered with the NH2‐overlayer were soaked in supersaturated solutions with respect to Ca2+ and PO43− ions [1.0SBF (simulated body fluid), which contains similar compositions to that in a living body and 1.5SBF in which only Ca2+ and PO43− concentrations are 1.5 times than that in 1.0SBF]. The experimental results demonstrated that HAp nucleation on an NH2‐overlayer is related to the electrostatic attractive force between positive NH2‐overlayer surface and negative incipient HAp microparticles homogeneously nucleated in 1.5SBF solution at 50°C. On the contrary, fewer HAp particles were observed on negatively charged “OH” terminated self‐assembled monolayer (SAM) because of the repulsive interaction. The Ca/P molar ratios of HAp particles increased from 0.92 at the beginning of nucleation in 1.5SBF to 1.63 in 14 days after growth in 1.0SBF at 37°C. After 14 days of soaking in 1.0SBF, a dense HAp film with the thickness up to 8.6 μm was formed on the NH2‐overlayer. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 294–304, 2002
Effect of poly(ethylene glycol) molecular weight on tensile and swelling properties of oligo(poly(ethylene glycol) fumarate) hydrogels for cartilage tissue engineering
Authors: Temenoff Johnna S. , Athanasiou Kyriacos A. , Lebaron Richard G. , Mikos Antonios G.
Published: October 2004

This study was designed to determine the effect of changes in poly(ethylene glycol) (PEG) molecular weight on swelling and mechanical properties of hydrogels made from a novel polymer, oligo(poly(ethylene glycol) fumarate) (OPF), recently developed in our laboratory. Properties of hydrogels made from OPF with initial PEG molecular weights of 860, 3900, and 9300 were examined. The PEG 3900 formulation had a tensile modulus of 23.1 ± 12.4 kPa and percent elongation at fracture of 53.2 ± 13.7%; the PEG 9300 formulation had similar tensile properties (modulus: 16.5 ± 4.6 kPa, elongation: 76.0 ± 26.4%). However, the PEG 860 gels had a significantly higher modulus (89.5 ± 50.7 kPa) and a significantly smaller percent elongation at fracture (30.1 ± 6.4%), when compared with other formulations. Additionally, there were significant differences in percent swelling between each of the formulations. Molecular weight between crosslinks (Mc) and mesh size were calculated for each OPF formulation. Mc increased from 2010 ± 116 g/mol with PEG 860 to 6250 ± 280 g/mol with PEG 9300. Mesh size calculations showed a similar trend (76 ± 2 Å for PEG 860 to 160 ± 6 Å for PEG 9300). It was also found that these hydrogels could be laminated if a second layer was added before the first had completely crosslinked. Mechanical testing of these laminated gels revealed that the presence of an interfacial area did not significantly alter their tensile properties. These results suggest that the material properties of OPF‐based hydrogels can be altered by changing the molecular weight of PEG used in synthesis and that multilayered OPF hydrogel constructs can be produced, with each layer having distinct mechanical properties. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 429–437, 2002
Low pressure plasma treatment of poly(3‐hydroxybutyrate): Toward tailored polymer surfaces for tissue engineering scaffolds
Authors: Nitschke Mirko , Schmack Gerhilt , Janke Andreas , Simon Frank , Pleul Dieter , Werner Carsten
Published: October 2004

Thin films of poly(3‐hydroxybutyrate) were modified by microwave ammonia plasma treatment. The results of the modification were studied by means of contact angle goniometry, ellipsometry, Fourier transform infrared–attenuated total reflection spectroscopy, atomic force microscopy, and X‐ray photoelectron spectroscopy. To prove the presence of amino groups on the poly(3‐hydroxybutyrate) surface, chemical labeling with 4‐trifluoromethyl benzaldehyde was performed before X‐ray photoelectron spectroscopy analysis. Under the applied plasma conditions, a hydrophilic surface with a good long‐term stability was obtained. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 632–638, 2002
Alginate type and RGD density control myoblast phenotype
Authors: Rowley Jon A. , Mooney David J.
Published: October 2004

Alginates are being increasingly used for cell encapsulation and tissue engineering applications; however, these materials cannot specifically interact with mammalian cells. We have covalently modified alginates of varying monomeric ratio with RGD‐containing cell adhesion ligands using carbodiimide chemistry to initiate cell adhesion to these polymers. We hypothesized that we could control the function of cells adherent to RGD‐modified alginate hydrogels by varying alginate polymer type and cell adhesion ligand density, and we have addressed this possibility by studying the proliferation and differentiation of C2C12 skeletal myoblasts adherent to these materials. RGD density on alginates of varying monomeric ratio could be controlled over several orders of magnitude, creating a range of surface densities from 1–100 fmol/cm2. Myoblast adhesion to these materials was specific to the RGD ligand, because adhesion could be competed away with soluble RGD in a dose‐dependent manner. Myoblast proliferation and differentiation could be regulated by varying the alginate monomeric ratio and the density of RGD ligands at the substrate surface, and specific combinations of alginate type and RGD density were required to obtain efficient myoblast differentiation on these materials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 217–223, 2002; DOI 10.1002/jbm.1287
Application of the multiensemble sampling to the hydration free energy
Authors: Han Kyu‐Kwang , Kim Ki Hae , Mhin Byung Jin , Son Hyeon S.
Published: October 2004

We demonstrate the feasibility of using multiensemble sampling method (MESM) to determine the free energy difference between two far states for which the configurational distributions do not overlap at all. The MESM is a recently developed non‐Boltzmann sampling technique. The free energy of charging a sodium ion in water is accurately calculated in a single simulation, introducing nine intermediate ionic states. This is due to the ability of the method to explore the relevant parts of configuration space equally for every state, and this ability comes from the universality of weighting function W and the simplicity in adjusting its parameters. Detailed procedures of adjusting the parameters are presented. The comparison with a free energy perturbation method (FEPM) shows that the MESM is more reliable and efficient. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1004–1009, 2001
Substituent effects on the Bergman cyclization of (Z)‐1,5‐hexadiyne‐3‐enes: a systematic computational study
Authors: Prall Matthias , Wittkopp Alexander , Fokin Andrey A. , Schreiner Peter R.
Published: October 2004

The effects of several substituents (BH2, BF2, AlH2, CH3, C6H5, CN, COCH3, CF3, SiH3, NH2, NH3+, NO2, PH2, OH, OH2+, SH, F, Cl, Br) on the Bergman cyclization of (Z)‐1,5‐hexadiyne‐3‐ene (enediyne, 3) were investigated at the Becke–Lee–Yang–Parr (BLYP) density functional (DFT) level employing a 6‐31G* basis set. Some of the substituents (NH3+, NO2, OH, OH2+, F, Cl, Br) are able to lower the barrier (up to a minimum of 16.9 kcal mol−1 for difluoro‐enediyne 7rr) and the reaction enthalpy (the cyclization is predicted to be exergonic for OH2+ and F) compared to the parent system giving rise to substituted 1,4‐dehydrobenzenes at physiological temperatures. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1605–1614, 2001
Resilience elements in students with learning disabilities
Authors: Miller Maurice
Published: October 2004

Seven elements of resilience are identified in college students who have learning disabilities. These elements become the bases for approaches to assisting children in constructing resilience when facing such difficulties. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 291–296, 2002.
Understanding family resilience
Authors: Patterson Joän M.
Published: October 2004

Families, as social systems, can be considered “resilient” in ways that parallel descriptions of individual resilience. In this article, the conceptualization of family‐level outcomes as a prerequisite for assessing family competence, and hence their resilience, is presented relative to the unique functions that families perform for their members and for society. The risk and protective processes that give rise to resilience in families are discussed in terms of family stress and coping theory, with a particular emphasis on the family's subjective appraisal of their sources of stress and their ability to manage them. An effort is made to distinguish two perspectives on resilience: exposure to significant risk as a prerequisite for being considered resilient versus promotion of strengths for all families in which life in general is viewed as risky. Implications for practitioners and policy makers in working with families to promote their resilience are discussed. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 233–246, 2002.
The metatheory of resilience and resiliency
Authors: Richardson Glenn E.
Published: October 2004

Resiliency and resilience theory is presented as three waves of resiliency inquiry. The identification of resilient qualities was the first wave characterized through phenomenological identification of developmental assets and protective factors. The second wave described resilience as a disruptive and reintegrative process for accessing resilient qualities. The third wave exemplified the postmodern and multidisciplinary view of resilience, which is the force that drives a person to grow through adversity and disruptions. Application of resilience using an educational and practical framework provides a means for connecting with and nurturing a client's resilience. Practical paradigms of resiliency that empower client control and choice are suggested. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 307–321, 2002.
Protective factors related to antisocial behavior trajectories
Authors: Morrison Gale M. , Robertson Laurel , Laurie Beth , Kelly Jennifer
Published: October 2004

A group of 115 fifth‐ and sixth‐grade Latino students were surveyed at the beginning and the end of the school year before their transition to middle or junior‐high school about their engagement in antisocial behaviors and about individual, social, and behavioral protective factors. The best predictors of decreases in antisocial behavior for these students, above and beyond variance for initial ratings and gender, were student perceptions of social support, parent supervision, and classroom participation. The importance of keeping students engaged in school academic work as a protection against antisocial behavior is emphasized as well as the need to help students gain skills necessary to access support for this academic work. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 277–290, 2002.
Heroes in the nursery: Three case studies in resilience
Authors: Rak Carl F.
Published: October 2004

This article examines the therapeutic work in three cases (child, adolescent, adult) to study the impact of a supportive and nurturing parent early in life upon the development of resilience. The close analysis of the clinical material of each client's personal narrative is the primary source. The metaphor of “heroes in the nursery” is posited as a vehicle for enhancing understandings of the development of resilience. Each case provides additive meaning to recent studies that elevate the importance of the memories of parents to the development of resilient responses of children later in life. Each case reveals specific dimensions of the impact of heroes in the nursery which extend our understandings of resiliency in children and adolescents as a proactive response to stress, trauma, and loss. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 247–260, 2002.
Abused child to nonabusive parent: Resilience and conceptual change
Authors: Wilkes Glenda
Published: October 2004

Individuals who were abused as children and have spontaneously, without intervention, been able to change their cognitive and behavioral patterns such that they do not abuse their own children represent a heretofore untapped source of information and understanding about the processes of conceptual change and resilience. This pilot study investigates the nature of this conceptual change as an exemplar of resilience. Birth order, gender, locus of control, and coping behaviors emerged as areas needing further study. Additionally, the belief on the part of the abusing parents that abuse was not wrong needs further investigation as a possible precursor to this particular context for conceptual change. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 261–276, 2002.
Facilitating police–minority youth attitude change: The effects of cooperation within a competitive context and exposure to typical exemplars
Authors: Rabois Dana , Haaga David A. F.
Published: October 2004

Previous community programs have been unsuccessful in changing youths' attitudes toward police, and have thus far not addressed police attitudes toward youth. In this pilot study, police (n = 26) competed together with minority youths (n = 51) on heterogeneous basketball teams. Pre‐ and postintervention attitudes toward youths/officers and posttest attitudes toward team members were examined. Police reported positive ratings of out‐group team members, and demonstrated a positive shift in attitude toward minority youth in general. Generalization of positive attitude was more likely when officers perceived their team members as typical exemplars of minority youth. Minority youths did not show a significant improvement in attitude toward police but reported favorable attitudes toward team members. Results suggest that a short‐term competitive tournament exposing individuals to typical exemplars may be effective for addressing hostile police attitudes toward minority youths. A controlled study is recommended to replicate and expand on our findings. © 2002 John Wiley & Sons, Inc.
Abusive home environments as predictors of poor adjustment during adolescence and early adulthood
Authors: Bank Lew , Burraston Bert
Published: October 2004

Unskilled discipline practices form the basis for three abusive elements that occur in the home environment: child maltreatment, neglectful supervision, and sibling conflict. Furthermore, we hypothesized that in the context of unskilled discipline, the abusive home environment variables would be predictive of a variety of adjustment outcomes as children moved into adolescence and early adulthood. We examined concurrent and longitudinal data for 182 Oregon Youth Study (OYS) boys across a variety of developmental outcomes over a 10‐year span. Multiple agent and method assessments of the boys, their siblings, and parents included direct observations, interviews, and questionnaires. Path analyses revealed that the consequences of each abusive home environment construct were, with little exception, consistent with the hypotheses. Thus, the enduring and powerful impact of an abusive home environment is apparent. This work also supports the idea of a continuum of parenting behaviors and a parenting skills deficit model across all families, rather than a “bad parent” versus “good parent” model. © 2001 John Wiley & Sons, Inc.
Disciplinary history, adult disciplinary attitudes, and risk for abusive parenting
Authors: Bower‐Russa Mary E. , Knutson John F. , Winebarger Allen
Published: October 2004

In an attempt to identify factors that could contribute to intergenerational physical abuse, the specific childhood disciplinary experiences of adolescents and young adults were assessed, and these childhood experiences were related to the subjects' assessment as to whether specific disciplinary tactics were abusive or appropriate in child rearing. Consistent with previous research, few maltreated persons viewed their own experiences as abusive. Moreover, personal experience with a disciplinary event was associated with a decreased tendency to view that particular form of discipline as inappropriate. Finally, a history of severe physical punishment, failure to acknowledge an abusive history when it had occurred, and adult attitudes regarding physical discipline were associated with selecting more punitive disciplinary strategies when individuals were faced with child misbehavior in an analog parenting task. © 2001 John Wiley & Sons, Inc.
Endogenous expression and localization of myostatin and its relation to myosin heavy chain distribution in C2C12 skeletal muscle cells
Authors: Artaza Jorge N. , Bhasin Shalender , Mallidis Con , Taylor Wayne , Ma Kun , Gonzalez‐Cadavid Nestor F.
Published: October 2004

Myostatin is a negative regulator of skeletal muscle growth. We have previously reported that recombinant myostatin protein inhibits DNA and protein synthesis in C2C12 cells. Our objective was to assess if C2C12 cells express myostatin, determine its sub‐cellular localization and the developmental stage of C2C12 cells in which myostatin mRNA and protein are expressed. To study the endogenous expression of myostatin, C2C12 myoblasts were allowed to progress to myotubes, and changes in the levels of endogenous myostatin mRNA expression were determined by RT–PCR. The myostatin protein and the two major myosin heavy chain (MHC) isoforms (MHC‐I and ‐II) were determined by Western blot. Confirmation of the relative MHC expression patterns was obtained by a modified polyacrylamide gel electropheretic (PAGE) procedure. Imunofluorescence staining was employed to localize the site of myostatin expression and the relative distribution of the MHC isoforms. Co‐expression of these proteins was studied using a dual staining approach. Expression of myostatin mRNA was found in myotubes but not in myoblasts. Myostatin protein was seen in most but not all, of the nuclei of polynucleated fibers expressing MHC‐II, and myostatin was detected in the cytoplasm of myotube. The localization of myostatin protein in myotube nuclei was confirmed by Western blot of isolated nuclear and cytoplasmic fractions. Incubation of C2C12 myotubes with graded doses of dexamethasone dose‐dependently increased the intensity of nuclear myostatin immunostaining and also resulted in the appearance of cytoplasmic expression. In conclusion, myostatin was expressed mostly in C2C12 myotubes nuclei expressing MHC‐II. Its predominant nuclear localization suggests that it may play a role in transcriptional regulation. J. Cell. Physiol. 190: 170–179, 2002. © 2002 Wiley‐Liss, Inc.
Recombinant transmembrane CD59 (CD59‐TM) confers complement resistance to GPI‐anchored protein defective melanoma cells*
Authors: De Nardo Chiara , Fonsatti Ester , Sigalotti Luca , Calabrò Luana , Colizzi Francesca , Cortini Enzo , Coral Sandra , Altomonte Maresa , Maio Michele
Published: October 2004

Protectin (CD59) is a glycosylphosphatidylinositol (GPI)‐anchored cell membrane glycoprotein, broadly expressed on melanocytic cells, that represents the main restriction factor of complement (C)‐mediated lysis of human melanoma cells. Levels of CD59 expression may impair the clinical efficacy of C‐activating monoclonal antibodies (mAb); thus, we investigated the molecular mechanisms underlying the lack of CD59 expression in selected melanoma cells. Serological and biochemical analyses showed that MeWo melanoma cells expressed CD59 neither at cell surface nor at cytoplasmic levels; however, no critical mutations were identified in their CD59 mRNA. Consistently, MeWo CD59 cDNA (MeWo‐CD59) was appropriately translated when transfected into the CD59‐positive Mel 100 melanoma cells, and into the CD59‐negative Nalm‐6 pre‐B leukemia cells that acquired resistance to C. In contrast, transfection of MeWo cells with CD59 cDNA from Mel 275 melanoma cells did not induce CD59 expression; however, their transfection with the CD59‐TM chimeric construct, obtained by replacing the GPI‐anchoring signal of MeWo‐CD59 with the transmembrane tail of the human low‐density lipoprotein receptor, induced the expression of a C‐protective transmembrane form of CD59. These data, together with the absent expression of additional GPI‐anchored proteins (i.e., CD55), suggest that defects in the biosynthesis and/or processing of GPI‐anchored proteins underlie the lack of CD59 expression in MeWo cells. Further unveiling of the molecular mechanism that turns off CD59 expression in human melanoma cells will help to set‐up more effective therapeutic strategies utilizing C‐activating mAb in melanoma patients. J. Cell. Physiol. 190: 200–206, 2002. © 2002 Wiley‐Liss, Inc.
Regulation of RNA polymerase II activity by CTD phosphorylation and cell cycle control
Authors: Oelgeschläger Thomas
Published: October 2004

The carboxyl‐terminal domain (CTD) of the largest subunit of mammalian RNA polymerase II (RNAP II) consists of 52 repeats of a consensus heptapeptide and is subject to phosphorylation and dephosphorylation events during each round of transcription. RNAP II activity is regulated during the cell cycle and cell cycle‐dependend changes in RNAP II activity correlate well with CTD phosphorylation. In addition, global changes in the CTD phosphorylation status are observed in response to mitogenic or cytostatic signals such as growth factors, mitogens and DNA‐damaging agents. Several CTD kinases are members of the cyclin‐dependent kinase (CDK) superfamily and associate with transcription initiation complexes. Other CTD kinases implicated in cell cycle regulation include the mitogen‐activated protein kinases ERK‐1/2 and the c‐Abl tyrosine kinase. These observations suggest that reversible RNAP II CTD phosphorylation may play a key role in linking cell cycle regulatory events to coordinated changes in transcription. J. Cell. Physiol. 190: 160–169, 2002. © 2002 Wiley‐Liss, Inc.
Borderline cystic tumors of the ovary: Gray‐scale and color Doppler sonographic findings
Authors: Pascual M. Angela , Tresserra Francisco , Grases Pedro J. , Labastida Ramon , Dexeus Santiago
Published: October 2004

Purpose

The aim of the study was to determine the value of gray‐scale and color Doppler sonography in distinguishing borderline cystic tumors (BCTs) from benign cysts and malignant tumors of the ovary.

Methods

The gray‐scale and color Doppler sonographic features of 383 ovarian lesions in 374 nonpregnant women were retrospectively studied. Sonography was performed transvaginally for all but 7 lesions, which were imaged suprapubically. All of the lesions were surgically resected via laparoscopy or laparotomy.

Results

The histopathologic diagnoses were 27 BCTs, 35 ovarian carcinomas, and 321 benign cysts. Sonography diagnosed 24 (89%) of 27 BCTs as malignant lesions. Patients with BCTs, were younger than those with ovarian cancer (p < 0.001). BCTs showed intracystic papillae in 17 cases (63%), diffuse internal echoes in 11 (41%), intracystic septa in 8 (30%), a heterogeneous echo pattern in 7 (26%), and a solid pattern in 4 (15%). BCTs showed blood flow in 24 cases (89%) and lower pulsatility and resistance indices (RI) compared with benign lesions (p < 0.001 for both). Multivariate analysis revealed intracystic papillae as the only independent predictor of BCTs (p < 0.001).

Conclusions

When a cystic mass has papillae, this is the only abnormal finding detected by gray‐scale transvaginal sonography, and color Doppler imaging shows low RI values within the mass, a BCT should be suspected. © 2002 John Wiley & Sons, Inc. J Clin Ultrasound 30:76–82, 2002; DOI 10.1002/jcu.10028
Prenatal sonographic diagnosis of diastrophic dwarfism
Authors: Tongsong Theera , Wanapirak Chanane , Sirichotiyakul Supatra , Chanprapaph Pharuhas
Published: October 2004

A healthy 27‐year‐old pregnant woman underwent sonographic examination because her uterine size was large for 20 weeks’ menstrual age. Sonograms showed short fetal limbs with hitchhiker thumbs and toes, thoracic scoliosis, clubbed feet, and polyhydramnios. The ossification of all bony structures appeared normal, and there was no evidence of fractures. On the basis of these sonographic findings, we diagnosed skeletal dysplasia and short‐limbed dwarfism, most likely diastrophic dwarfism. We counseled the parents, and the pregnancy was continued. At 37 weeks menstrual age, the patient vaginally delivered a male infant that weighed 2,560 g. The infant survived with respiratory support during his first few days of life. Postnatal physical and radiologic examinations confirmed the prenatal diagnosis of diastrophic dwarfism. Sonography is the modality of choice for prenatal detection of diastrophic dwarfism. © 2002 John Wiley & Sons, Inc. J Clin Ultrasound 30:103–105, 2002; DOI 10.1002/jcu.10032
Sonographic examination of the oral phase of swallowing: Bolus image enhancement
Authors: Casas Michael J. , Seo Anna H. , Kenny David J.
Published: October 2004

Purpose

The purpose of this study was to evaluate the ability of 4 liquid boluses to enhance pixel brightness and the ease with which the boluses could be identified during the sonographic evaluation of oral swallowing in healthy young adults.

Methods

Ten healthy adult volunteers (5 men and 5 women), ranging in age from 21 to 31 years, underwent sonographic evaluation of the oral phase of swallowing while sitting in their usual feeding position. We compared the ability of the 4 following liquids to improve sonographic visualization of swallowing with that of water: a carbonated cola beverage, 5.0 ml of Thick‐It in 120 ml of water, 2.5 ml of Thick‐It in 120 ml of water, and 7.5 ml of confectioners' sugar in 120 ml of water. Water was used as a control. In each case, 5 ml of the liquid was introduced into the subject's oral cavity using a syringe, and the subject was instructed to swallow. Digitized still images and recorded video sequences of sonographic examinations of the swallowing were analyzed. The brightness of the bolus image on selected digitized video frames was measured digitally using Image Analyst software. Pixel brightness within selected regions of interest for each of the test liquids was statistically compared with that for water. Seven clinicians rated the visualization of each test liquid and water on paired sonographic videotape sequences. These ratings and the level of agreement between them were statistically tested.

Results

Only the carbonated cola beverage demonstrated statistically greater pixel brightness than that of water on digitized video frames (p = 0.01), whereas both cola (with a moderate inter‐rater agreement, κ = 0.50) and 5.0 ml Thick‐It mixed with 120 ml of water (with a fair inter‐rater agreement, κ = 0.24) were significantly better visualized on sonographic video sequences.

Conclusions

The digital still‐frame analysis confirmed the clinicians' ratings of bolus visualization on real‐time sonography, but dynamic sonography is more important than still frames in assessing sonographic swallow media because the dynamic images more closely parallel what is seen in clinical practice. Future investigations of sonographic contrast agents for use in the examination of the oral phase of swallowing should use both static digital (still‐frame) and dynamic (real‐time) assessment methods, as well as expert reviewers. © 2002 John Wiley & Sons, Inc. J Clin Ultrasound 30:83–87, 2002; DOI 10.1002/jcu.10034
Isolation of the peri‐acrosomal plasma membrane protein D40 enriched fraction from guinea pig spermatozoa using a monoclonal antibody
Authors: Ilayperuma I.
Published: October 2004

Membrane fragments were obtained from guinea pig spermatozoa by mechanical shearing. A membrane‐enriched fraction was separated from other cellular debris, mainly sperm nuclei and tails, by centrifugation on 20% Ficoll 70 solution. Peri‐acrosomal plasma membrane protein, D40, enriched fraction was separated from this membrane preparation using a mouse monoclonal antibody to D40 attached to magnetic beads. Enrichment of D40 antigen in this fraction was demonstrated by western blotting. The method provides a preparative route to a membrane, the constituents of which play an important role in sperm recognition of the zona pellucida and the acrosome reaction. Some constituents of the peri‐acrosomal plasma membrane over the equatorial segment of the acrosome may also play a role in sperm docking with the oocyte plasma membrane and fusion of the two cells. J. Exp. Zool. 292:402–410, 2002. © 2002 Wiley‐Liss, Inc.
Characterization and quantification of yolk proteins in the lobster, Homarus americanus
Authors: Tsukimura Brian , Waddy Susan L. , Vogel Jacalyn M. , Linder Colby J. , Bauer Daniel K. , Borst David W.
Published: October 2004

Yolk protein (vitellin, Vn) and its precursor (vitellogenin, Vg) were isolated and characterized in the ovary and hemolymph, respectively, of the adult female lobster, Homarus americanus. Vn had a molecular mass of 360 kDa when analyzed by gel filtration. When analyzed by SDS‐PAGE, Vn had six bands (110, 105, 94, 90, 81, and 78 kDa). An anti‐Vn antiserum was developed using purified Vn, and the antiserum was used to detect Vn and Vg by ELISA and western blot techniques. ELISA analysis of hemolymph proteins separated by gel filtration indicated that Vg was similar in mass to Vn (360 kDa). However, western blots of hemolymph proteins separated by SDS‐PAGE indicated that Vg contained a pair of protein subunits, 194 kDa and 179 kDa. Furthermore, the elution profiles of Vn and Vg from anion exchange chromatography indicated that Vg had a more negative charge. Thus, Vg appears to be processed after its uptake by the ovary to form Vn. Vg was undetectable in hemolymph from adult males by either ELISA or by western blot analysis. However, hemolymph levels of Vg in adult females increased 40‐fold during the reproductive cycle, rising from 18 μg/mL in ovarian stage II to 789 μg/mL at stage V. This increase correlates well with oocyte growth during the cycle. Hence, this method may be useful for studying the regulation of lobster vitellogenesis. J. Exp. Zool. 292:367–375, 2002. © 2002 Wiley‐Liss, Inc.
Effects of chemical anoxia on adrenergic responses of goldfish hepatocytes and the contribution of α‐ and β‐adrenoceptors
Authors: Manzl Claudia , Schubert Markus , Schwarzbaum Pablo J. , Krumschnabel Gerhard
Published: October 2004

Adrenergic responses during normoxia and chemical anoxia were investigated in anoxia‐tolerant hepatocytes from the goldfish, Carassius auratus. Epinephrine‐stimulated glucose release was unaltered after 1 hr of chemical anoxia, the concentration of epinephrine required for half maximal stimulation of glucose release (K) ranging from 0.62 × 10–8 to 2.05 × 10–8 M. Similarly, the maximum rate of glucose release caused by hormonal stimulation was not affected by chemical anoxia. In anoxic goldfish hepatocytes [Ca2+]i remained constant in nonstimulated cells but could be elevated by addition of epinephrine. The magnitude of this [Ca2+]i‐increase was dependent on the concentration of the catecholamine and this dependency was similar under normoxia (K = 1.17 × 10–8 M) and chemical anoxia (K = 1.15 × 10–8 M), as was the percentage of cells responding (77%) and displaying oscillatory [Ca2+]i response patterns (60%) after epinephrine addition, although the frequency of [Ca2+]i oscillations was significantly lower in anoxic cells. To analyze a possible shift in the importance of α‐ and β‐adrenoceptors during chemical anoxia, the effect of phentolamine and propranolol, α‐ and β‐adrenergic antagonists respectively, on epinephrine‐stimulated glucose release was studied. Application of the α‐antagonist caused a dose‐dependent reduction of glucose‐release which was similar under both conditions, whereas the sensitivity to the β‐antagonist was lowered after chemical anoxia. Taken together these results provide evidence that during chemical anoxia goldfish hepatocytes remain responsive to adrenergic stimulation and that there is a partial shift regarding the contribution of α‐ and β‐adrenergic pathways to the induction of cellular glucose release stimulated by epinephrine. J. Exp. Zool. 292:468–476, 2002. © 2002 Wiley‐Liss, Inc.
Costs of anorexia during pregnancy in a viviparous snake (Vipera aspis)
Authors: Lourdais Olivier , Bonnet Xavier , Doughty Paul
Published: October 2004

Spontaneous anorexia has been documented in various animal species and is usually associated with activities competing with food intake. In natural conditions, most female aspic vipers (Vipera aspis) stop feeding during the two months of pregnancy. We carried out a simple experiment on 40 pregnant females to determine whether anorexia was obligatory or facultative, and to investigate the energetic consequence of fasting on post‐partum body condition and litter traits. Three diet treatments were applied during gestation: no food, one feeding occasion, and two feeding occasions. Twelve nonpregnant, unfed females were used as a control group. Most gravid females accepted captive mice during gestation, suggesting that anorexia reported in the field was a side effect of the tremendous changes in activity pattern associated with pregnancy. Mass loss was high for unfed reproductive females, indicating high energy expenditure associated with embryo maintenance. Prey consumption allowed compensation for metabolic expenditure and enhanced post‐partum female body condition, but had no effects on litter characteristics. The magnitude of the metabolic expenditure during gestation appeared to be independent of fecundity. J. Exp. Zool. 292:487–493, 2002. © 2002 Wiley‐Liss, Inc.