bluuebunny/crossref_metadata_2025 huggingface dataset:
Isomers of C20: An energy profile
Authors: Greene Katherine R. , Beran Kyle A.
Published: August 2002

Semiempirical calucaltions, at the PM 3 level, are used to geometrically optimize and determine the absolute energies (heats of formation) of a variety of C20 isomers. Based on the geometrically optimized Cartesian coordinates of the ring and the bowl isomers, and the subsequent saddle‐point calculation, a two‐dimensional energy profile between these two isomers is generated. Performing geometry optimization on the Cartesian coordinates that correspond to energy minima within the ring–bowl profile, we have been able to identify several more isomers of C20 that are predicted to be energitically stable. With these additional stable structures, we have identified pairs of isomers that lie adjacent to one another on the potential energy surface, as is evidenced by the form of their respective energy profiles. These adjacent pairs of isomers establish a step‐wise transformation between the ring and the bowl. This process, which extends out over the three‐dimensional surface, is predicted to require less energy than that of the direct, two‐dimensional transformation predicted in the ring–bowl profile. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 938–942, 2002
Large set of P3‐decompositions
Authors: Kang Qingde , Zhang Yanfang
Published: August 2002

Let G=(V(G),E(G)) be a graph. A (n,G, λ)‐GD is a partition of the edges of λKn into subgraphs (G‐blocks), each of which is isomorphic to G. The (n,G,λ)‐GD is named as graph design for G or G‐decomposition. The large set of (n,G,λ)‐GD is denoted by (n,G,λ)‐LGD. In this work, we obtain the existence spectrum of (n,P3,λ)‐LGD. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 151–159, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10008
Pathways from family economic conditions to adolescents' distress: Supportive parenting, stressors outside the family, and deviant peers
Authors: Barrera Manuel , Prelow Hazel M. , Dumka Larry E. , Gonzales Nancy A. , Knight George P. , Michaels Marcia L. , Roosa Mark W. , Tein JennYun
Published: August 2002

Economic hardship is a stressor that affects large numbers of children and their families. This study estimated a model that included pathways linking economic conditions to the internalizing and externalizing symptoms of a multiethnic sample of urban adolescents. Similar to other prominent models, this model included parental distress and parenting as key constructs, but the expanded ecological model also included stressors outside the family and adolescents' associations with deviant peers as possible explanatory factors. Data from 300 adolescents and their parents were consistent with a model that showed linkages between economic conditions, parental depressive symptoms, supportive parenting, and internalizing symptoms. Stressors outside the family were associated with deviant peer affiliations which, in turn, predicted internalizing and externalizing symptoms. The implications of these findings for understanding economic conditions' influence on adolescents' mental health are discussed. © 2002 John Wiley & Sons, Inc.
Correspondence between youth report and census measures of neighborhood context
Authors: Herrenkohl Todd I. , Hawkins J. David , Abbott Robert D. , Guo Jie
Published: August 2002

Many studies that have examined neighborhood factors as predictors of crime have used census data. Exclusive use of these data limits the range of neighborhood factors that can be assessed and the frequency with which assessments can be made. Surveys of neighborhood residents provide an alternative data source. However, survey data have been viewed as reflecting the individual perceptions of respondents rather than characteristics of neighborhoods themselves. This study sought to determine whether survey data could be used to measure neighborhood context and whether data from nonrepresentative samples of youth are adequate to do so. This was achieved by examining the consistency between measures of neighborhood disadvantage/disorganization developed from the 1990 national census and from surveys of youth given in the same year as part of the Seattle Social Development Project (SSDP). The study found strong correspondence between the contemporaneous measures. The results suggest that survey data can be used to measure neighborhood factors. Advantages of this method are discussed. © 2002 Wiley Periodicals, Inc.
Cultural factors in help‐seeking for child behavior problems: Value orientation, affective responding, and severity appraisals among Chinese‐American parents
Authors: Lau Anna , Takeuchi David
Published: August 2002

This study explored the relationships between cultural values, appraisal of child behavior problems, and associated help‐seeking intentions among Chinese‐American parents. Questionnaires were administered to 120 Chinese‐American parents of elementary‐school‐aged children. Parents were asked how they might respond if their child displayed the behavioral problems depicted in a hypothetical vignette. Influences of Chinese value orientation, severity appraisal, and affective reactions on help‐seeking intentions were examined using regression analyses and structural equation modeling. The study examined three hypotheses regarding the nature of the influence of cultural value orientation on help‐seeking intentions: (a) a direct effect model, (b) an indirect effect through cultural differences in severity appraisal, and (c) an indirect effect through cultural differences in affective responding. Results supported the hypothesis that cultural value orientation exerted an indirect effect on help‐seeking intentions through its influence on affective responding. Those parents who had more traditional Chinese values responded with more feelings of shame to child behavior problems and, in turn, reported lower intentions to seek help. Findings are discussed with reference to the literature on help‐seeking among Asian Americans. © 2001 John Wiley & Sons, Inc.
CCKB/gastrin receptor mediates synergistic stimulation of DNA synthesis and cyclin D1, D3, and E expression in Swiss 3T3 cells
Authors: Zhukova Elena , Sinnett‐Smith James , Wong Helen , Chiu Terence , Rozengurt Enrique
Published: August 2002

In order to develop a model system for identifying signaling pathways and cell cycle events involved in gastrin‐mediated mitogenesis, we have used high efficiency retroviral‐mediated transfection of cholecystokinin (CCK)B/gastrin receptor into Swiss 3T3 cells. The retrovirally‐transfected CCKB/gastrin receptor binds 125I‐CCK‐8 with high affinity (Kd = 1.1 nM) and is functionally coupled to intracellular signaling pathways including rapid and transient increase in Ca2+ fluxes, protein kinase C‐dependent protein kinase D activation, and MEK‐dependent ERK1/2 activation. In the presence of insulin, CCK‐8 or gastrin induced a 66.5 ± 8.8‐fold (mean ± SEM, n = 24 in eight independent experiments) increase in cellular DNA synthesis, reaching a level similar to that achieved by stimulation with a saturating concentration of fresh serum, and much greater than the response to each agonist added alone. CCK‐8 also induced a striking increase in the expression of cyclins D1, D3, and E and hyperphosphorylation of Rb acting synergistically with insulin. Similar effects were observed when CCKB/gastrin receptor was activated in the presence of EGF or bombesin. Our results demonstrate that activation of CCKB/gastrin receptor retrovirally‐transfected into Swiss 3T3 induces a potent synergistic effect on DNA synthesis, accumulation of cyclins D1, D3, and E and hyperphosphorylation of Rb in combination with insulin, EGF, or bombesin. Thus, the CCKB/gastrin receptor transfected into Swiss 3T3 cells provides a novel model system to elucidate mitogenic signal transduction pathways and cell cycle events activated via this receptor. © 2001 Wiley‐Liss, Inc.
BMP‐2 and BMP‐9 promotes chondrogenic differentiation of human multipotential mesenchymal cells and overcomes the inhibitory effect of IL‐1
Authors: Majumdar Manas Kumar , Wang Eunice , Morris Elisabeth Ann
Published: August 2002

Bone morphogenetic proteins play important roles in connective tissue morphogenesis. In this study, we used human multipotential mesenchymal cells as a target to analyze the effect of bone morphogenetic proteins on chondrogenesis. We also analyzed the effect of proinflammatory cytokine interleukin‐1 on chondrogenic‐differentiated cells and the interaction of IL‐1β with bone morphogenetic proteins. Cells placed in a 3‐dimensional matrix of alginate beads and cultured in a serum‐free media with bone morphogenetic protein‐2 and ‐9 induced expression of type II collagen (Col2A1) mRNA and increased expression of aggrecan and cartilage oligomeric matrix protein suggesting chondrogenic differentiation of the cells. The transcription factor Sox‐9 that regulates both Col2A1 and aggrecan gene expression showed increased expression with BMP treatment. Chondrogenic differentiated cells treated with interleukin‐1 decreased Sox‐9, Col2A1 and aggrecan gene expression. Removal of interleukin‐1 and further addition of bone morphogenetic proteins resulted in returned expression of chondrogenic markers. Chondrogenic differentiated cells cultured in the presence of different concentrations of bone morphogenetic proteins and interleukin‐1 showed that bone morphogenetic proteins were able to partially block the suppressive effect of interleukin‐1. This study shows that bone morphogenetic proteins play an important role in chondrogenesis and may prove to be potential therapeutics in cartilage repair. © 2001 Wiley‐Liss, Inc.
Roads to polyploidy: The megakaryocyte example
Authors: Ravid Katya , Lu Jun , Zimmet Jeffrey M. , Jones Matthew R.
Published: August 2002

Polyploidy, recognized by multiple copies of the haploid chromosome number, has been described in plants, insects, and in mammalian cells such as, the platelet precursors, the megakaryocytes. Several of these cell types reach high ploidy via a different cell cycle. Megakaryocytes undergo an endomitotic cell cycle, which consists of an S phase interrupted by a gap, during which the cells enter mitosis but skip anaphase B and cytokinesis. Here, we review the mechanisms that lead to this cell cycle and to polyploidy in megakaryocytes, while also comparing them to those described for other systems in which high ploidy is achieved. Overall, polyploidy is associated with an orchestrated change in expression of several genes, of which, some may be a result of high ploidy and hence a determinant of a new cell physiology, while others are inducers of polyploidization. Future studies will aim to further explore these two groups of genes. J. Cell. Physiol. 190: 7–20, 2002. © 2002 Wiley‐Liss, Inc.
Lipopolysaccharide supports survival and fusion of preosteoclasts independent of TNF‐α, IL‐1, and RANKL
Authors: Suda Koji , Woo Je‐Tae , Takami Masamichi , Sexton Patrick M. , Nagai Kazuo
Published: August 2002

Lipopolysaccharide (LPS), a cell component of Gram‐negative bacteria, is a pathogen of inflammatory bone loss. To examine the effects of LPS on the survival and fusion of osteoclasts, mononuclear osteoclasts (preosteoclasts, pOCs) were collected from a mouse co‐culture system and cultured in the presence or absence of LPS. Most pOCs died within 24 h in the absence of any stimulus. LPS as well as receptor activator of NF‐κB ligand (RANKL) supported the survival of pOCs, and induced their fusion to form multinucleated cells (MNCs). Like authentic osteoclasts, MNCs induced by LPS expressed calcitonin receptors, and formed actin rings on culture plates. LPS‐induced MNC formation in pOC cultures was observed even in the presence of osteoprotegerin and interleukin (IL)‐1‐receptor antagonists. MNC formation was also stimulated by LPS in pOC cultures prepared from tumor necrosis factor (TNF)‐receptor‐I or TNF‐receptor‐II deficient mice. LPS induced the degradation of IκB in pOCs within 20 min. Lactacystin, an inhibitor of NF‐κB activation, and wortmannin, an inhibitor of phosphatidylinositol‐3 kinase, strongly inhibited LPS‐induced MNC formation in pOC cultures. LPS induced pit‐forming activity of pOCs in the presence of macrophage‐colony stimulating factor (M‐CSF). These findings suggest that LPS stimulates the survival and fusion of pOCs, independent of RANKL, IL‐1 or TNF‐α action. Activation of NF‐κB and phosphatidylinositol‐3 kinase appeared to be involved in LPS‐induced effects on pOCs. These observations suggest that LPS is involved directly in inflammatory bone loss, and also indirectly through the production of LPS‐induced host factors such as IL‐1 and TNF‐α. J. Cell. Physiol. 190: 101–108, 2002. © 2002 Wiley‐Liss, Inc.
Effect of protein kinase inhibitors on the stretch‐elicited c‐Fos and c‐Jun up‐regulation in human PDL osteoblast‐like cells
Authors: Kletsas Dimitris , Basdra Efthimia K. , Papavassiliou Athanasios G.
Published: August 2002

Osteoblastic cells transduce signals of mechanical loading that plays a key role in maintaining bone formation. In an attempt to elucidate the biochemical events associated with the conversion of mechanical stress to biological outcome, we examined cultured human periodontal ligament (hPDL) osteoblastic cells exposed to continuous stretch, in terms of cellular parameters correlating known signaling cascades to the initial phase of osteoblast‐specific transcriptional control. Time‐course experiments revealed that mechanical stretch‐loaded hPDL cells exhibit a very rapid and relatively sustained increase in the abundance of the immediate‐early gene products, c‐Fos and c‐Jun, components of the activator protein‐1 (AP‐1) transcription factor. Moreover, this increase in protein levels was accompanied by hyperphosphorylation and thereby potentiation of c‐Jun, the principal modulator of AP‐1 activity. Importantly, these inductive effects were partly or completely abolished by pre‐incubating the cells with SB 203580, PD 098059, and the novel compound Y‐27632, inhibitors of p38 mitogen‐activated protein kinase (MAPK), MAPK kinase (MEK), and Rho‐associated protein kinase (RhoK), respectively. These results consolidate AP‐1 as the pivotal downstream effector in the early response of hPDL cells to continuous mechanical stretching, via the coordinate stimulation of de novo synthesis and post‐translational regulation of AP‐1 proteins. This “integrating” function of AP‐1 is mediated through a mechanotransduction circuit that incorporates elements of well‐defined upstream signaling protein kinase systems. J. Cell. Physiol. 190: 313–321, 2002. © 2002 Wiley‐Liss, Inc.
Induction of KDR expression in bovine arterial endothelial cells by thrombin: Involvement of nitric oxide
Authors: Wang Jie , Morita Ikuo , Onodera Mitsue , Murota Sei‐itsu
Published: August 2002

Thrombin, a multifunctional serine protease, is generated at the site with vascular injuries. It not only participates in the coagulation cascade, but also can induce a lot of events related to cell mitogenesis and migration. In this study, we investigated the effect of thrombin on endothelial cell proliferation induced by vascular endothelial growth factor (VEGF). Thrombin promoted proliferation of cultured bovine carotid endothelial cells in a time‐ and dose‐dependent manner. Moreover, it drastically enhanced the cell growth stimulated by VEGF. This stimulatory effect was reduced by inhibitors of either protein kinase C (PKC) or mitogen‐activated protein kinase kinase (MAPKK). Thrombin induced a significant increase in the level of mRNA of the kinase domain‐containing receptor (KDR), but not tms‐like tyrosine kinase (Flt‐1), in a time‐dependent manner, which reached the maximum after 24 h of stimulation. This increase coincides well with the KDR protein expression. The luciferase assay showed that thrombin induced an about 7.5‐fold increase in the KDR promoter activity compared with the control. This enhanced KDR promoter activity was also abolished by inhibitors of either PKC or MAPKK. The deletion analyses indicated that the region between −115 and −97 (containing Sp1 binding region) within the KDR promoter gene was required for the enhanced KDR expression induced by thrombin and VEGF. Moreover, the nitric oxide synthase (NOS) inhibitor abolished both the accelerated cell proliferation and the increased KDR expression induced by thrombin and VEGF. This inhibition was abrogated by DETA NONOate, a NO donor with long half‐life. These findings suggest that thrombin might potentiate the VEGF‐induced angiogenic activity through increasing the level of the VEGF receptor KDR, in which production of NO is involved. J. Cell. Physiol. 190: 238–250, 2002. © 2002 Wiley‐Liss, Inc.
Stimulation of the proliferation and differentiation of mouse pink‐eyed dilution epidermal melanocytes by excess tyrosine in serum‐free primary culture
Authors: Hirobe Tomohisa , Wakamatsu Kazumasa , Ito Shosuke , Abe Hiroyuki , Kawa Yoko , Mizoguchi Masako
Published: August 2002

The epidermal cell suspensions of the neonatal dorsal skin derived from wild type mouse at the pink‐eyed dilution (p) locus (black, C57BL/10JHir‐P/P) and their congenic mutant mouse (pink‐eyed dilution, C57BL/10JHir‐p/p) were cultured with a serum‐free melanocyte growth medium supplemented with additional L‐tyrosine (Tyr) from initiation of the primary culture. L‐Tyr inhibited the proliferation of P/P melanocytes in a dose‐dependent manner, whereas L‐Tyr stimulated the proliferation of p/p melanoblasts and melanocytes regardless of dose. On the other hand, L‐Tyr stimulated (P/P) or induced (p/p) the differentiation of epidermal melanocytes in a dose‐dependent manner. In both P/P and p/p melanoblasts and melanocytes cultured with 2.0 mM L‐Tyr for 14 days, slight increases in contents of eumelanin marker, pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and pheomelanin marker, aminohydroxyphenylalanine (AHP) were observed. The average number of total melanosomes (stages I, II, III, and IV) per P/P melanocyte was not changed by L‐Tyr treatment, but the proportion of stage IV melanosomes in the total melanosomes was increased. On the contrary, in p/p melanoblasts and melanocytes L‐Tyr increased dramatically the number of stage II, III, and IV melanosomes as well as the proportion of stage III melanosomes. Contents of PTCA and eumelanin precursor, 5,6‐dihydroxyindole‐2‐carboxylic acid (DHICA) of cultured media in p/p melanocytes were much more greatly increased than in P/P melanocytes. However, contents of AHP and pheomelanin precursor, 5‐S‐cysteinyldopa (5‐S‐CD) of cultured media in p/p melanocytes were increased in a similar tendency to P/P melanocytes. These results suggest that p/p melanocytes in the primary culture are induced to synthesize eumelanin by excess L‐Tyr, but difficult to accumulate them in melanosomes. J. Cell. Physiol. 191: 162–172, 2002. © 2002 Wiley‐Liss, Inc.
Febrile and acute hyperthermia enhance TNF‐induced necrosis of murine L929 fibrosarcoma cells via caspase‐regulated production of reactive oxygen intermediates
Authors: Leroux E. , Auzenne E. , Weidner D. , Wu Z.Y. , Donato N.J. , Klostergaard J.
Published: August 2002

Previous studies have demonstrated the essential role of TNF‐induced reactive oxygen intermediates (ROI) in the necrosis of L929 cells. We investigated the molecular basis for the interaction of hyperthermia and TNF in these cells. Hyperthermia, both febrile (40.0–40.5°C) and acute (41.5–41.8°C), strongly potentiated TNF killing, and sensistization was significantly quenched by the antioxidant, BHA. The broad‐spectrum caspase inhibitor, Z‐VAD, has been shown to markedly increase the TNF sensitivity of L929 cells at 37°C; we observed that hyperthermia would also enhance the sensitivity of L929 cells to TNF + Z− VAD and that BHA could significantly quench the response, as well. The basis for hyperthermic potentiation was unlikely thermally‐increased sensitivity to ROI, as treatment with hydrogen peroxide for 24 h killed L929 cells essentially equivalently, whether incubated continuously at 37°C or at 40.0–40.5°C, or for 2 h at 41.5–41.8°C. However, febrile and acute hyperthermia markedly increased TNF‐induced production of ROI, with or without Z‐VAD. Hyperthermia dramatically accelerated the onset of this production, as well as the onset of necrotic death, as determined by oxidation of dihydro‐rhodamine and propidium iodide staining, respectively, both of which were significantly quenchable with BHA. We conclude that hyperthermia potentiates TNF‐mediated killing in this cell model primarily by increasing the afferent, and not the efferent, phase of TNF‐induced necrosis. © 2001 Wiley‐Liss, Inc.
Addition of designer enhancers to functional foods: need also for redesigned biocatalysts in fail‐clean strategies of bioprocessing?
Authors: Wiseman Alan , Woods Len
Published: August 2002

© 2001 Society of Chemical Industry
Activated carbon surface modifications by adsorption of bacteria and their effect on aqueous lead adsorption
Authors: Rivera‐Utrilla J , Bautista‐Toledo I , Ferro‐García M A , Moreno‐Castilla C
Published: August 2002

The adsorption of Escherichia coli on different activated carbons has been studied. The activated carbon samples used have been characterized, determining their surface area, pore size distribution, elemental analysis, mineral matter analysis and pH of the point of zero charge. The adsorption capacity of these carbons increased with their hydrophobicity and macropore volume. The number of bacteria adsorbed on the demineralized activated carbon in a solution of pH value equal to the iso‐electric point of the carbon was negligible. However, in the presence of cations the proportions of bacterial cells adsorbed were 87.8% (Fe3+), 54.7% (Ca2+) and 24.8% (Mg2+) respectively. This increase in adsorption capacity in the presence of electrolytes has been explained on the basis of both the reduction in electrostatic free energy and the increase in cell surface hydrophobicity due to the metal bound by some compounds of the cell membrane. When the solution pH was intermediate between the pH values of the point of zero charge of the carbon and bacteria the number of bacteria adsorbed increased due to the attractive interactions between the carbon and bacteria. The adsorption of bacteria on activated carbons decreased the porosity and increased the negative charge density of the latter. Depending on the experimental conditions used, the presence of bacteria can enhance the capacity of activated carbons to adsorb lead.

© 2001 Society of Chemical Industry
Chemical removal of PCBs from water samples under ambient conditions
Authors: Nollet Hendrik , Lutgen Pierce , Verstraete Willy
Published: August 2002

Liquids and sludges containing polychlorinated biphenyls (PCBs) can be treated to concentrate the PCBs in a solid residue. The latter can then be handled to destroy the PCBs. In the first part of this work, procedures are explored by which 2,3,4‐trichlorobiphenyl (TCB) and 2,2′,3,3′,4,5,6‐heptachlorobiphenyl (HeCB) are insolubilised, flocculated and removed from the water. The results demonstrate that application of Fe(III)‐oxyhydroxide precipitation permits effective and reversible co‐precipitation of TCB and HeCB. Fly ash from coal‐fired thermal powerplants and CaO can be used as well for the rapid removal of TCB and HeCB. In the second part of this work, rapid insolubilisation followed by the degradation of TCB and HeCB by zero‐valent iron powder in anaerobic batch systems is presented. Zero‐valent iron was also used for the reductive dechlorination/remediation of TCB and HeCB sorbed on the fly ash and CaO particles. Overall, this paper describes a methodology to rapidly concentrate the PCBs from water and to concomitantly detoxify them in the concentrate by a chemical reductive process under ambient conditions of pH and temperature.

© 2002 Society of Chemical Industry
The fermentation of mixtures of D‐glucose and D‐xylose by Candida shehatae, Pichia stipitis or Pachysolen tannophilus to produce ethanol
Authors: Sánchez Sebastián , Bravo Vicente , Castro Eulogio , Moya Alberto J , Camacho Fernando
Published: August 2002

The fermentation of mixtures of D‐glucose and D‐xylose by three non‐traditional yeasts: Candida shehatae (ATCC 34887), Pachysolen tannophilus (ATCC 32691) and Pichia stipitis (ATCC 58376) have been studied to determine the optimal strain and initial culture conditions for the efficient production of ethanol. The comparison was made on the basis of maximum specific growth rate (µm), biomass productivity, the specific rates of total substrate consumption (qs) and ethanol production (qE) and the overall yields of ethanol and xylitol. All the experiments were performed in stirred‐tank batch reactors at a temperature of 30 °C. The initial pH of the culture medium was 4.5. The highest values of µm (above 0.5 h−1) were obtained with P stipitis in cultures containing high concentrations of D‐xylose. All three yeasts consumed the two monosaccharides in sequence, beginning with D‐glucose. The values of qs diminished during the course of each experiment with all of the yeasts. The highest values of the specific rates of total substrate consumption and ethanol production were obtained with C shehatae (for t = 10 h, qs and qE were above 5 g g−1 h−1 and 2 g g−1 h−1, respectively), although the highest overall ethanol yields were fairly similar with all three yeasts, at around 0.4 g g−1.

© 2002 Society of Chemical Industry
Duplex sonographic criteria for measuring carotid stenoses
Authors: Staikov Ivan N. , Nedeltchev Krassen , Arnold Marcel , Remonda Luca , Schroth Gerhard , Sturzenegger Matthias , Herrmann Cornelia , Rivoir Anita , Mattle Heinrich P.
Published: August 2002

Purpose

The aim of this retrospective study was to determine optimal duplex sonographic criteria for use in our institution for diagnosing severe carotid stenoses and to correlate those findings with angiographic measurements obtained by the European Carotid Surgery Trial (ECST), North American Symptomatic Carotid Endarterectomy Trial (NASCET), and Common Carotid (CC) methods of grading carotid stenoses.

Methods

We analyzed the angiographic data using the ECST, NASCET, and CC methods and compared the results with the duplex sonographic findings. We then calculated the sensitivity, specificity, positive and negative predictive values, and accuracy of the duplex sonographic method. Taking these parameters into account, the optimal intrastenotic peak systolic velocity (PSV) and end diastolic velocity (EDV) were derived for diagnosing severe stenoses according to the 3 angiographic methods.

Results

Optimal PSV and EDV values for diagnosing a 70% or greater stenosis in our laboratory were as follows: with the NASCET method of angiographic grading of stenoses, PSV 220 cm/second or greater and EDV 80 cm/second or greater, and with the ECST and CC methods, PSV 190 cm/second or greater, and EDV 65 cm/second or greater. The optimal PSV and EDV for diagnosing a stenosis of 80% or greater with the ECST grading method were 215 cm/second or greater and 90 cm/second or greater, respectively.

Conclusions

Duplex sonography is a sensitive and accurate tool for evaluating severe carotid stenoses. Optimal PSVs and EDVs vary according to the angiographic method used to grade the stenosis. They are similar for stenoses 70% or greater with the NASCET method and for stenoses 80% or greater with the ECST method. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:275–281, 2002; Published online in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/jcu.10078
Lymphatic networks in the periodontal tissue and dental pulp as revealed by histochemical study
Authors: Matsumoto Yuushi , Zhang Bi , Kato Seiji
Published: August 2002

The structural organization and fine distribution of the lymphatic networks in the periodontal tissues (gingiva, periodontal membrane, and alveolar process) and dental pulp of animals and humans were reviewed with special reference to histochemical examination by light and electron microscopy. The distinction between lymphatics and blood vessels was made on cryostat sections of undecalcified and calcified teeth treated with EDTA solution and whole mount preparations of periodontal membranes using 5′‐nucleotidase (5′‐Nase)‐alkaline phosphatase (ALPase) double staining. This staining procedure allowed lymphatic vessels in the periodontal tissue and dental pulp to be differentiated from blood vessels. The specificity and localization of the enzyme reactions were confirmed by comparative histochemical studies of the same specimen with light microscopy and scanning or transmission electron microscopy. Well‐developed 5′‐Nase‐positive lymphatic networks were observed on the tissue sections and whole mount preparations of the gingiva, periodontium, and dental pulp. More lymphatic vessels were seen in the root area of the periodontium than in the cervical area. In the dental pulp, lymphatic vessels were more numerous in the central part than in the peripheral odontoblastic layer. These distributions of the lymphatic capillary networks are discussed in relation to their ability to supply lymph to the teeth. Microsc. Res. Tech. 56:50–59, 2002. © 2002 Wiley‐Liss, Inc.
Adrenomedullin in the adrenal
Authors: Kapas Supriya , Hinson Joy P.
Published: August 2002

Adrenomedullin (AM) was originally characterized in extracts of an adrenal medullary tumor. Since this original finding the peptide and its mRNA have also been found in the adrenal cortex, specifically, in the cells of the aldosterone‐secreting zona glomerulosa. It is clear that the synthesis of AM is actively regulated in both cortex and medulla. Much research effort has been focused on identifying a role for AM in the adrenal gland. To date, no consistent effect on medullary catecholamine biosynthesis has been demonstrated. In the cortex the actions of AM are controversial and appear to depend on both the tissue preparation used and on the specific receptor population expressed in the individual gland. The results of further studies on the long‐term actions of AM on adrenal growth and differentiation are awaited with interest. Microsc. Res. Tech. 57:91–97, 2002. © 2002 Wiley‐Liss, Inc.
Effects of Fragile X syndrome and an FMR1 knockout mouse model on forebrain neuronal cell biology
Authors: Churchill James D. , Beckel‐Mitchener Andrea , Weiler Ivan Jeanne , Greenough William T.
Published: August 2002

The neurological deficits exhibited by patients with Fragile X syndrome (FraX) have been attributed to the absence of the Fragile X Mental Retardation Protein (FMRP), the product of the FMR1 gene, which is nonfunctional in these individuals. While a great deal has been learned about FraX using non‐invasive techniques and autopsy tissue from humans, the limited availability of subjects and specimens severely restricts the rate at which such data can be collected and the types of experimental questions posed. In view of these limitations, a transgenic mouse model of FraX has been constructed in which the FMR1 gene is selectively knocked out (KO) [Bakker et al. (1994) Cell 78:23–33]. These mice show molecular, morphological, and behavioral alterations consistent with phenotypes observed in FraX patients, making them good models to study the absence of FMRP expression. Microsc. Res. Tech. 57:156–158, 2002. © 2002 Wiley‐Liss, Inc.
Modulation of podocyte phenotype in collapsing glomerulopathies
Authors: Barisoni Laura , Kopp Jeffrey B.
Published: August 2002

Podocytes are well‐differentiated postmitotic cells whose function is largely based on their complex cytoskeletal architecture. In diseases with proteinuria, podocytes undergo morphologic changes. Podocytes react to an injurious stimulus by a reorganization of their foot process architecture that is independent of the primary injury and the cause of the proteinuria. Collapsing glomerulopathies, including the idiopathic and secondary forms due to HIV infection, have been previously considered a part of the focal sclerosing glomerulosclerosis (FSGS) spectrum. However, in contrast to FSGS, both forms of collapsing glomerulopathy are characterized by segmental and global collapse of the glomerular basement membrane (GBM) and by characteristic ultrastructural alterations in podocytes. These alterations include loss of the actin‐based cytoskeleton, a dysregulated/dedifferentiated phenotype, cellular hypertrophy, and cell proliferation. These observations raise the following questions: 1) What mechanism causes glomerular collapse and do podocytes have a role? We recently proposed that in collapsing glomerulopathies the composition of the GBM is altered and contains more immature forms of collagen IV. These observations suggest that dedifferentiated/dysregulated podocytes may participate in remodeling the GBM composition, producing fetal collagen isoforms. 2) What is the pathomechanism underlying podocyte dysregulation? Although it is still unclear which etiologic factors are responsible for the idiopathic forms of collapsing glomerulopathy, in situ hybridization studies in a transgenic mouse model of HIV‐associated collapsing glomerulopathy and on renal biopsies of patients with HIV‐associated collapsing glomerulopathy demonstrated the presence of the HIV‐1 RNA in podocytes and tubular epithelial cells. These findings suggest a direct link between viral gene expression and the dysregulation of the podocyte phenotype. 3) Another open question is how podocytes become infected in HIV‐associated collapsing glomerulopathy. HIV‐1 typically uses CD4 and a co‐receptor such as CCR5 or CXCR4 to enter cells. So far, there is no demonstration of the expression of these receptors in podocytes. These negative findings, however, do not exclude the possibility that in the kidney another, CD4 independent, co‐receptor may be used for viral cell entry. Finally, is it important to mention that collapsing glomerulopathies have a high prevalence in black patients, suggesting a link between racial background and the virus‐related podocyte injury. Microsc. Res. Tech. 57:254–262, 2002. Published 2002 Wiley‐Liss, Inc.
Calcium signalling in cells of oligodendroglial lineage
Authors: Soliven Betty
Published: August 2002

Intracellular Ca2+ is the key signal that regulates the efficacy of neurotransmitter release and synaptic plasticity in neurons but is also an important second messenger involved in the signal transduction and modulation of gene expression in both excitable and non‐excitable cells. Glial cells, including cells of oligodendroglial (OLG) lineage, are capable of responding to extracellular stimuli via changes in the intracellular Ca2+. This review article focuses on the mechanisms of Ca2+ signalling in cells of OLG lineage with the goal of providing the basis for understanding the relevance of receptor‐ and non‐receptor‐mediated signalling to oligodendroglial development, myelination, and demyelination. Conclusions to date indicate that cells of OLG lineage exhibit remarkable plasticity with regard to the expression of ion channels and receptors linked to Ca2+ signalling and that perturbation of [Ca2+]i homeostasis contributes to the pathogenesis of demyelinating diseases. Microsc. Res. Tech. 52:672–679, 2001. © 2001 Wiley‐Liss, Inc.
Meningeal nociception: Electrophysiological studies related to headache and referred pain
Authors: Messlinger Karl , Ellrich Jens
Published: August 2002

Headaches, which are usually referred to characteristic sites of the skull, are believed to involve meningeal nociceptors located in the dura mater encephali. Animal experiments show that these meningeal nociceptors are polymodal and usually highly sensitive to mechanical stimulation. These properties are also characteristic for the second order neurons in the spinal trigeminal nucleus, most of which receive convergent input from facial receptive sites. Sensitization of primary and secondary neurons by chemical irritants to mechanical stimuli may be an important mechanism in the generation of headaches. The convergent input from extracranial structures, which seems to be differentially organized in rodents and man, may explain the typical features of referred headache. Targets for analgesics used in the therapy of headaches (non‐steroidal antiinflammatory drugs, 5‐HT1 receptor agonists) are probably meningeal nociceptors and different sites of the central trigeminal nociceptive and antinociceptive pathways. Microsc. Res. Tech. 53:129–137, 2001. © 2001 Wiley‐Liss, Inc.
Histological demonstration of increased vascular permeability in the dura mater of the rat
Authors: Dux Mária , Messlinger Karl
Published: August 2002

Neurogenic inflammation of the dura mater encephali has been suggested to play an important role in the pathophysiology of headaches. Although functional studies using extravasation techniques indicate an enhanced permeability of blood vessels after chemical or electrical stimulation of C‐fibres supplying the dura mater, histological demonstration of leaky blood vessels is still a problem. We used the vascular labelling method combined with i.v. injection of colloidal silver solution to test the permeability increasing effect of intravenous administration of substance P, topical application of mustard oil or acidic phosphate buffer and local electrical stimulation of the exposed dura mater. Histological characteristics of increased vascular permeability were observed exclusively after mustard oil and acidic phosphate buffer. This observation may indicate different mechanisms of increased vascular permeability involving pinocytosis and formation of interendothelial gaps selectively visualized by the vascular labelling method. Microsc. Res. Tech. 53:229–231, 2001. © 2001 Wiley‐Liss, Inc.
Cell culture model for antiulcerogenic agents
Authors: Terano Akira , Hiraishi Hideyuki , Shimada Tadahito , Takahashi Morio , Yoshiura Kenta , Horie‐Sakata Kaori
Published: August 2002

To elucidate the mechanisms of antiulcerogenic agents, we established the cell culture model derived from rat gastric epithelium. The cultured cells were identified as mucus‐producing cells by using histological analysis. This culture model is useful for investigating the untiulcer effect of various agents and to reveal the mechanisms of the drug action. In particular, the ulcer‐healing model using the cultured monolayer is promising and convenient for the study of several growth factors such as HGF as well as antiulcerogenic agents. The effect of polaporezinc in the cultured model is introduced. Microsc. Res. Tech. 53:389–395, 2001. © 2001 Wiley‐Liss, Inc.
Immune response to autologous and heterologous Helicobacter pylori antigens in humans
Authors: Jakob Benjamin , Birkholz Sabine , Schneider Thomas , Duchmann Rainer , Zeitz Martin , Stallmach Andreas
Published: August 2002

Infection of humans with Helicobacter pylori results in the development of chronic gastritis and plays an important role in gastric ulcer pathogenesis. Despite the infiltration of the mucosa with specific immunocompetent cells and production of specific antibodies, the infection usually persists for life. This study was performed to investigate if immunologic mechanisms exist which could contribute to the inability of the host to terminate the infection. Therefore, we compared the in vitro immunoreactivity of peripheral blood mononuclear cells (PBMC) from H. pylori‐infected patients after stimulation with sonicated H. pylori bacteria from the stomach of the patient (autologous bacterial strain) with stimulation by bacteria from other patients (heterologous bacteria). We measured cell proliferation, expression of T cell activation markers CD25, HLA‐DR, and CD71, as well as production of interleukin‐10 (IL‐10), an inhibitory cytokine. We found that the proliferative response of PBMC was significantly lower after autologous than after heterologous stimulation. Furthermore, secretion of IL‐10 in the culture supernatants was significantly higher when PBMC were incubated with autologous than with heterologous H. pylori antigens. No significant differences between autologous or heterologous stimulation were observed in the increased expression of T cell activation markers. These data indicate that systemic immunologic response to H. pylori are strain‐dependent. For further studies of the immune responses towards H. pylori, the use of an autologous stimulatory system seems necessary. Microsc. Res. Tech. 53:419–424, 2001. © 2001 Wiley‐Liss, Inc.
Ion channels in cultured microglia
Authors: Walz Wolfgang , Bekar Lane K.
Published: August 2002

Inward and, depending on activation state, outward potassium currents are the dominant ion channels in microglial cells in culture. During transition between resting and activated phases, there is also an upregulated expression of stretch/swelling‐activated chloride currents. Pharmacological blockade of the specific potassium channels does not prevent the transition, whereas blockade of chloride channels does, suggesting that this current may be involved in phase changes. Interestingly, this chloride current is far less studied than the potassium currents with regard to the different microglial phases. One puzzling finding when studying microglial state is that despite changes in current densities and membrane oscillations during transition, there is no evidence of an accompanying change in membrane potential. In other cells of the immune system, membrane oscillations and alterations in membrane potential are correlated with transitions in cellular phases. This discrepancy in microglia may be a result of the fact that almost all ion channel and membrane potential studies in culture are undertaken with concomitant dialysis of cytoplasm with pipette solution. Further complicating matters is that the few studies that use microglia in situ, find fundamental differences in ion channel current patterns of “resting” microglia as well as different temporal changes to pathological events or stimuli. Microsc. Res. Tech. 54:26–33, 2001. © 2001 Wiley‐Liss, Inc.
Phagocytic properties of microglia in vitro: Implications for a role in multiple sclerosis and EAE
Authors: Smith Marion E.
Published: August 2002

The microglial cell, after many years of neglect, has become recognized as the sole representative cell of the immune system that resides in the normal central nervous system. While normally dormant, microglia can be activated by secretory substances or signals associated with disease or injury, and becomes a phagocytic cell, which also produces its own injurious molecules. In the activating process, its morphology is changed from a resting process‐bearing cell, into a rounded amoebic form, and displays new or increased amounts of functional markers, such as receptors and Class I and Class II MHC molecules. Microglia prepared from newborn mice or rats for tissue culture are already activated, and can be used for studies of their phagocytic properties. Although they can phagocytize foreign substances, their uptake and metabolism of myelin are emphasized here, in keeping with their role in demyelinating diseases. A number of receptors have been implicated and appear to be important in the attachment to, and ingestion of, myelin particles in vitro, including the Fc, complement, macrophage scavenger, and the Galectin‐3/MAC‐2 receptors, although the α2‐macroglobulin/low‐density lipoprotein receptor and mannose receptors have also been suggested as participants in myelin phagocytosis. Certain cytokines and adhesion molecules also regulate the phagocytic activity of microglia. Comparative in vitro studies of phagocytosis by peritoneal macrophages and microglia have shown that the two kinds of cells respond differently to regulatory molecules, and it is concluded that they have different innate properties. The role of microglia in the demyelinative diseases experimental autoimmune encephalomyelitis and multiple sclerosis is emphasized here, and the possible means of intervention in the process leading to myelin destruction is discussed. Microsc. Res. Tech. 54:81–94, 2001. Published 2001 Wiley‐Liss, Inc.
Distribution of sex steroid hormone receptors in the avian brain: Functional implications for neural sex differences and sexual behaviors
Authors: Gahr Manfred
Published: August 2002

Developmental and seasonal changes in the production of androgens, estrogens, and progestins seem to control sex‐specific differentiation and seasonal changes in appetitive and consummatory sexual behaviors of birds. This results in profound sex differences in the quality (sex‐specific) or quantity (sex‐typical) of behaviors such as courtship, territoriality, or copulation. Steroids affect the brain by binding to intracellularly located receptors. The same brain areas express androgen, estrogen, and progesterone receptors in male and female brains. Sex differences in these genetically determined patterns occur in the size of neuron populations that intrinsically express sex steroid receptors. Further permanent sex differences are subsequent to degenerative fates of receptor expressing neuron populations during ontogeny. Transient sex differences in receptor expression appear to be due to area‐specific up‐ and down‐regulation of receptor levels, reflecting transient changes in the level of circulating steroids, changes in environmental conditions, or in the physiological status of the individuals. In particular, intrinsic sex differences in the expression pattern of sex steroid receptors and steroid‐independent regulation of the expression level of these receptors in the brain are limiting mechanisms for gonad‐dependent sexual development and activities. Microsc. Res. Tech. 55:1–11, 2001. © 2001 Wiley‐Liss, Inc.
Vitellogenin from female and estradiol‐stimulated male river lampreys (Lampetra fluviatilis L.)
Authors: Mewes Karsten Rüdiger , Latz Martin , Golla Holger , Fischer Albrecht
Published: August 2002

The influence of estradiol‐17β (E2) on vitellogenesis is well documented for a number of oviparous craniates. We have examined the role that estradiol‐17β plays in the induction and regulation of vitellogenin synthesis in the maturing European river lamprey, Lampetra fluviatilis. In both females and males the estradiol‐17β concentrations in the plasma reached comparable maximum values in March, only a few weeks before spawning. Throughout the spawning run, the vitellogenin titer in the blood of females remains rather constant while the ovary volume increases. In contrast, we never found circulating VTG in untreated male lampreys. The synthesis and secretion of the yolk precursor molecule can be induced in males, however, by high doses of estradiol injected into the coelom. Lamprey vitellogenin was isolated from the blood of maturing females as well as from hormone‐stimulated males and identified by its immunological and electrophoretic properties. In the blood plasma of both maturing female and estradiol‐treated male lampreys it always appears simultaneously in two different molecular forms: a vitellogenin monomer with an apparent molecular weight of 310–330�kDa and a dimer. After SDS treatment, vitellogenin is represented as a 212‐kDa polypeptide. J. Exp. Zool. 292:52–72, 2002. © 2002 Wiley‐Liss, Inc.