bluuebunny/crossref_metadata_2025 huggingface dataset:
Transgenic Expression of 11β-Hydroxysteroid Dehydrogenase Type 2 in Osteoblasts Reveals an Anabolic Role for Endogenous Glucocorticoids in Bone
Authors: Sher Lorin B. , Woitge Henning W. , Adams Douglas J. , Gronowicz Gloria A. , Krozowski Zygmunt , Harrison John R. , Kream Barbara E.
Published: November 2003

Glucocorticoid excess leads to bone loss, primarily by decreasing bone formation. However, a variety of in vitro models show that glucocorticoids can promote osteogenesis. To elucidate the role of endogenous glucocorticoids in bone metabolism, we developed transgenic (TG) mice in which a 2.3-kb Col1a1 promoter fragment drives 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) expression in mature osteoblasts. 11β-HSD2 should metabolically inactivate endogenous glucocorticoids in the targeted cells, thereby reducing glucocorticoid signaling. The inhibitory effect of 300 nm hydrocortisone on percent collagen synthesis was blunted in TG calvariae, demonstrating that the transgene was active. Collagen synthesis rates were lower in TG calvarial organ cultures compared with wild-type. Trabecular bone parameters measured by microcomputed tomography were reduced in L3 vertebrae, but not femurs, of 7- and 24-wk-old TG females. These changes were also not seen in males. In addition, histomorphometry showed that osteoid surface was increased in TG female vertebrae, suggesting that mineralization may be impaired. Our data demonstrate that endogenous glucocorticoid signaling is required for normal vertebral trabecular bone volume and architecture in female mice.
Distribution of the VPAC2 Receptor in Peripheral Tissues of the Mouse
Authors: Harmar Anthony J. , Sheward W. John , Morrison Christine F. , Waser Beatrice , Gugger Mathias , Reubi Jean Claude
Published: November 2003

The neuropeptide vasoactive intestinal peptide (VIP) exerts its actions through two structurally related G protein-coupled receptors (VPAC1 and VPAC2). Pituitary adenylate cyclase-activating polypeptide (PACAP) is also a potent agonist of VPAC1 and VPAC2 receptors as well as of a third, PACAP-specific receptor (PAC1). We report here the distribution of the VPAC2 receptor in peripheral tissues of the mouse, determined by receptor autoradiography using [125I]VIP and the selective VPAC2 receptor agonist [125I]Ro25-1553 in wild-type and VPAC2 receptor-null mice. In addition, displacement experiments with the VPAC2-selective agonist Ro25-1553 and the VPAC1-selective agonist [K15,R16,L27]VIP(1–7)/GRF(8–27) were performed using the universal radioligand [125I]VIP. The VPAC2 receptor is found predominantly in smooth muscle (in blood vessels and in the smooth muscle layers of the gastrointestinal and reproductive systems), the basal part of the mucosal epithelium in the colon, lung, the vasculature of the kidney, adrenal medulla, and retina. Unexpectedly, the receptor was also present in thyroid follicular cells and acinar cells of the pancreas, tissues that have not been found to express the receptor in other species, and in very large amounts in the lung. Our data suggest novel functions of the VPAC2 receptor and additional potential therapeutic uses of drugs acting at the receptor (including the treatment of erectile dysfunction), but our results also indicate that caution should be exercised in using the mouse as an animal model for the evaluation of VIP analogs intended for diagnostic or therapeutic use in man.
Negative Regulation of Insulin-Stimulated Mitogen-Activated Protein Kinase Signaling By Grb10
Authors: Langlais Paul , Dong Lily Q. , Ramos Fresnida J. , Hu Derong , Li Yunhua , Quon Michael J. , Liu Feng
Published: November 2003

Grb10 is a Pleckstrin homology and Src homology 2 (SH2) domain-containing protein that binds to the tyrosine-phosphorylated insulin receptor in response to insulin stimulation. Loss of Grb10 function in mice results in fetal and placental overgrowth; however, the molecular mechanism remains unknown. In the present study, we show that overexpression of Grb10 in Chinese hamster ovary cells expressing the insulin receptor or in 3T3-L1 adipocytes reduced insulin-stimulated phosphorylation of MAPK. Overexpression of Grb10 in rat primary adipocytes also inhibited insulin-stimulated phosphorylation of the MAPK downstream substrate Elk1. To determine the mechanism by which Grb10 inhibited insulin-stimulated MAPK signaling, we examined whether Grb10 affects the phosphorylation of MAPK upstream signaling components. We found that overexpression of Grb10 inhibited the insulin-stimulated phosphorylation of Shc, a positive regulator of the MAPK signaling pathway. The inhibitory effect was diminished when the SH2 domain of Grb10 was deleted. The negative role of Grb10 in insulin signaling was established by suppression of endogenous Grb10 by RNA interference in HeLa cells overexpressing the insulin receptor, which enhanced insulin-stimulated phosphorylation of MAPK, Shc, and Akt. Taken together, our findings suggest that Grb10 functions as a negative regulator in the insulin-stimulated MAPK signaling pathway. In addition, the inhibitory effect of Grb10 on the MAPK pathway is most likely due to a direct block of insulin-stimulated Shc tyrosine phosphorylation.
Encore facilitates SCF-Ubiquitin-proteasome-dependent proteolysis duringDrosophilaoogenesis
Authors: Ohlmeyer Johanna Talavera , Schüpbach Trudi
Published: November 2003

Exit from the cell cycle requires the downregulation of Cyclin/Cdk activity. In the ovary of Drosophila, Encore activity is necessary in the germline to exit the division program after four mitotic divisions. We find that in encore mutant germaria, Cyclin A persists longer than in wild type. In addition, Cyclin E expression is not downregulated after the fourth mitosis and accumulates in a polyubiquitinated form. Mutations in genes coding for components of the SCF pathway such as cul1, UbcD2 and effete enhance the extra division phenotype of encore. We show that Encore physically interacts with the proteasome, Cul1 and Cyclin E. The association of Cul1, phosphorylated Cyclin E and the proteasome 19S-RP subunit S1 with the fusome is affected in encore mutant germaria. We propose that in encore mutant germaria the proteolysis machinery is less efficient and, in addition, reduced association of Cul1 and S1 with the fusome may compromise Cyclin E destruction and consequently promote an extra round of mitosis.
Individual microtubule dynamics contribute to the function of mitotic and cytoplasmic arrays in fission yeast
Authors: Sagolla Meredith Johnson , Uzawa Satoru , Cande W. Zacheus
Published: November 2003

Schizosaccharomyces pombe is an excellent organism for studying microtubule dynamics owing to the presence of well-defined microtubule arrays that undergo dramatic rearrangements during various stages of the cell cycle. Using sensitive time-lapse video microscopy and kymographic analysis, we have determined the polymerization/depolymerization kinetics of individual microtubules within these arrays throughout the fission yeast cell cycle. Interphase bundles are composed of 4-7 microtubules that act autonomously, demonstrating that individual microtubules are responsible for mediating the functions ascribed to these arrays. The nucleation and growth of cytoplasmic microtubules is inhibited upon cellular transition into mitosis, leading to their gradual disappearance. At the onset of mitosis, microtubules form on the nuclear face of the spindle pole body and exhibit dramatically increased dynamics. The presence of these intra-nuclear astral microtubules (INA) is reminiscent of spindle assembly and the search and chromosome capture mechanism observed in metazoan cells. Consistent with other in vivo studies, we do not observe microtubule flux in the anaphase B spindle. Finally, the depolymerization of individual microtubules alternates between each half-spindle, resulting in spindle collapse during telophase. On the basis of these observations, we conclude that microtubules in these diverse cytoskeletal arrays have autonomous behaviors that are an essential component of any model describing cell-cycle-dependent changes in the behavior and function of microtubule arrays.
Activity of the human papillomavirus E6 PDZ-binding motif correlates with an enhanced morphological transformation of immortalized human keratinocytes
Authors: Watson Richard A. , Thomas Miranda , Banks Lawrence , Roberts Sally
Published: November 2003

Human papillomavirus E6 oncoproteins induce the proteasomal degradation of several multi-PDZ (PSD95/Dlg/ZO-1) domain-containing proteins such as the human homologue of Drosophila discs large. Binding to PDZ domain-containing proteins is mediated by a PDZ-binding motif contained within the C-terminus of E6. The ability of E6 proteins to induce degradation of PDZ domain-containing proteins correlates with their oncogenic potential. Here we examined the biological effect of this region of the human papillomavirus type 18 E6 oncoprotein on keratinocyte morphology. Our results show that in simian virus 40-immortalized human keratinocytes, stable expression of E6 correlated with the induction of an exaggerated mesenchymal-like morphology and actin cytoskeleton disorganization compared with parental cells. The altered phenotype was accentuated in cells expressing an E6 protein containing a mutation (Arg153Leu) within a protein kinase A recognition motif that abrogates protein kinase A's negative regulation of the activity of the PDZ-binding domain. The E6-induced changes indicated an epithelial-mesenchymal transition and were supported by the finding that E6-expressing cells contained vimentin. Changes to the epithelial phenotype of cells expressing a mutant E6 protein (Thr156Glu) that is unable to degrade discs large was significantly less marked, although they did show evidence of epithelial-mesenchymal transition. These observations imply that the activity of the E6 PDZ-binding motif contributes only to a part of the transition. Further analysis of the E6 cell lines showed a decrease in adherens junction and desmosome formation. Cells expressing a functional PDZ-binding motif showed the greatest disruption of intercellular junction formation, but this did not correlate with a decrease in total cellular levels of the individual components of adhesion junctions. This suggests that the activity of the PDZ-binding motif may have influenced either the assembly or integrity of functional adhesion complexes. An E6-mediated decrease in peripheral membrane levels of PDZ proteins like discs large could be the basis for the enhanced morphological transformation of immortalized keratinocytes.
The vimentin cytoskeleton regulates focal contact size and adhesion of endothelial cells subjected to shear stress
Authors: Tsuruta Daisuke , Jones Jonathan C. R.
Published: November 2003

Recently, we reported that vimentin-type intermediate filaments, in addition to microfilaments, associate with αvβ3 integrin-positive focal contacts in endothelial cells. To gain insight into intermediate filament-focal contact interaction, we induced expression of yellow fluorescent protein (YFP)-integrin β3 and cyan fluorescent protein (CFP)-vimentin protein in endothelial cells. At least 50% of the YFP-β3 integrin-labeled focal contacts associated with CFP-labeled vimentin intermediate filaments in live cells. Moreover, focal contacts and intermediate filaments moved in concert in the plane of the membrane and assembling focal contacts were sites of vimentin filament assembly. When endothelial cells were subjected to flow, large focal contacts assembled and associated with thick vimentin bundles. These large focal contacts showed minimal dynamic activity. Cells in which vimentin expression had been inhibited by RNA interference assembled smaller than normal focal contacts. More dramatically, such cells showed decreased adhesion to the substratum. These data provide evidence that the vimentin cytoskeleton regulates focal contact size and helps stabilize cell-matrix adhesions in endothelial cells.
An inhibition of cyclin-dependent kinases that lengthens, but does not arrest, neuroepithelial cell cycle induces premature neurogenesis
Authors: Calegari Federico , Huttner Wieland B.
Published: November 2003

The G1 phase of the cell cycle of neuroepithelial cells, the progenitors of all neurons of the mammalian central nervous system, has been known to lengthen concomitantly with the onset and progression of neurogenesis. We have investigated whether lengthening of the G1 phase of the neuroepithelial cell cycle is a cause, rather than a consequence, of neurogenesis. As an experimental system, we used whole mouse embryo culture, which was found to exactly reproduce the temporal and spatial gradients of the onset of neurogenesis occurring in utero. Olomoucine, a cell-permeable, highly specific inhibitor of cyclin-dependent kinases and G1 progression, was found to significantly lengthen, but not arrest, the cell cycle of neuroepithelial cells when used at 80 μM. This olomoucine treatment induced, in the telencephalic neuroepithelium of embryonic day 9.5 to 10.5 mouse embryos developing in whole embryo culture to embryonic day 10.5, (i) the premature up-regulation of TIS21, a marker identifying neuroepithelial cells that have switched from proliferative to neuron-generating divisions, and (ii) the premature generation of neurons. Our data indicate that lengthening G1 can alone be sufficient to induce neuroepithelial cell differentiation. We propose a model that links the effects of cell fate determinants and asymmetric cell division to the length of the cell cycle.
Yielding of the clamped-wire system in the Ilizarov external fixator
Authors: Watson M A , Matthias K J , Maffulli N , L Hukins D W
Published: November 2003

This study demonstrates that the clamped-wire system used to suspend bones within an Ilizarov external fixator yields when the perpendicular load exceeds 50 N per wire. Cyclic loading was applied to tensioned wires clamped within an Ilizarov ring component, with steadily increasing load amplitude. Wires were tested at four initial tension settings. The amount of energy lost within the clamped-wire system per load cycle was calculated for every test. The results showed that there was a consistent trend to increasing non-recoverable energy loss per load cycle when peak loads exceed 50 N for all initial tension settings. A finite element (FE) model replicating the experimental conditions was performed to investigate the levels of stress within the loaded wires. The FE model analyses showed that high stresses were generated in the wires close to the clamping sites, and that the stress levels could reasonably be expected to exceed the material yield stress when loaded to about 55 N, for all initial tension settings. The results show that material yield, accompanied by some wire slippage through the clamps, is responsible for system yield, in agreement with previous studies. Although the initial wire tension has an appreciable effect on the wire stiffness, it did not affect the elastic load range of the clamped-wire system. To prevent yield of the clamped-wire system in practice, the fixator should be assembled with sufficient wires to ensure that the load transmitted to each wire by the patient does not exceed 50 N.
Moment generation in wheelchair propulsion
Authors: Guo Lan-Yuen , Zhao K D , Su Fong-Chin , An Kai-Nan
Published: November 2003

Wheelchair propulsion is a man-machine interaction in which chair design and fit affect the relative positions and orientations of the upper extremity relative to the handrim and wheel axle. To understand these relationships better, experimental data were collected in five hand positions from five subjects exerting maximal effort to propel an instrumented wheelchair with its wheel in a locked position. The results of experiments revealed that the progression moment was greater at both initial and terminal propulsion positions and smaller in the mid-propulsion position. The vertical and horizontal force components were directed radially away from the wheel axle posterior to the dead centre position and radially towards the wheel axle anterior to top dead centre. Subsequently, a subject-specific quasi-static model of the upper extremity which maximized wheel progression moment was developed to augment our understanding of experimental measures. Model-predicted trends in progression moments and hand force direction were similar to experiment. Model predictions revealed that the optimal progression moment generation could potentially be affected by an individual's anthropometric parameters, joint strengths and also the direction of force applied by the hand on the handrim. Through wheelchair fitting and training of wheelchair users, it may be possible to improve propulsion technique.
Characterization of Polyesters by Matrix-Assisted Laser Desorption/Ionization and Fourier Transform Mass Spectrometry
Authors: Mize Todd H. , Simonsick William J. , Amster I. Jonathan
Published: November 2003

Two homopolyesters, poly(neopentyl glycol- alt-isophthalic acid) and poly(hexanediol- alt-azelaic acid), and two copolyesters, poly[dipropoxylated bisphenol-A- alt-(isophthalic acid- co-adipic acid)] and poly[neopentyl glycol- alt-(adipic acid- co-isophthalic acid)] were analyzed by internal-source matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FT-MS). The high resolution and high mass accuracy provided by FT-MS greatly facilitate the characterization of the polyester and copolyester samples. Isobaric resolution allows the ion abundances of overlapping isotopic envelopes to be assessed. Repeat units were confirmed and end group functionality assigned. Single-shot mass spectra of the entire polymeric distribution demonstrate that the dynamic range of this internal MALDI source instrument and the analyzer cell exceeds the performance previously reported for higher field instruments. Corrections of space–charge mass shift effects are demonstrated for the analytes using an external calibrant and (subsequent to confirmation of structure) using internal calibration, which removes the ambiguity due to space–charge differences in calibrant and analyte spectra. Capillary gel-permeation chromatography was used to prepare low polydispersity samples from a high polydispersity polyester, improving the measurement of molecular weight distribution two-fold while retaining the benefits of high resolution mass spectrometry for elucidation of oligomer identity.
Derivatization in Mass Spectrometry—2. Acylation
Authors: Zaikin Vladimir G. , Halket John M.
Published: November 2003

The present review is devoted to acylation as a widely employed derivatization procedure for protection of OH (alcohols, polyols, phenols, enols), SH (thiols) and NH (amines, amides) groups in order to increase volatility, improve chromatographic properties and, if possible, improve mass spectral properties of derivatives. Chemical aspects of derivatization and various acylating agents are characterized. Mass spectral [electron ionization (EI), chemical ionization (CI) and negative-ion (NI) CI] properties of derivatives that are helpful in identification, structure elucidation and quantitative determination of the analyzed compounds are discussed. Some recent analytical applications of the procedure in synthetic organic chemistry, clinical chemistry, environmental chemistry etc. are summarized.
Stereospecific Ion—Molecule Reactions of Anabolic-Type Steroid Tertiary Alcohols with Proton-Donating Cations
Authors: Zaikin Vladimir G. , Borisov Roman S.
Published: November 2003

Isobutane and methane chemical ionization (CI) mass spectra of C-17a-epimeric, 17a-substituted 3-methoxyestra-1,3,5(10),8-tetraen-17a-ols and at C-17-epimeric 17-substituted 3-methoxyestra-1,3,5(10)-trien-17-ols, as well as of some their derivatives, have been studied. In each epimeric pair, the peak intensity ratio [MH–H2O]+ / [MH]+ is greater for stereoisomers having an axial (or quasi-axial) hydroxyl group. The same regularity in the peak intensity ratio [MH–CH3COOH]+ / [MH]+ is valid for acetates in the D-homo series. The observed quantitative differences in CI mass spectra of epimers are explained by steric hindrance of the attack of the proton-donating cation caused by the angular 18-methyl group. No differences in the ease of elimination of the silanol molecule were observed in CI mass spectra of epimeric silyl ethers.
Investigation of 4-(Nitrophenylamino)Pent-3-En-2-Ones and 4-(Nitrobenzylamino)Pent-3-en-2-Ones by Electron Ionization Mass Spectrometry. Observation of Characteristic Ortho Effects
Authors: Frański Rafał , Gierczyk Błażej , Fiedorow Piotr , Chadyniak Dariusz , Urbaniak Włodzimierz
Published: November 2003

The compounds 4-(phenylamino)pent-3-en-2-ones (1–3) and 4-(benzylamino)pent-3-en-2-ones (4–6) substituted with a nitro group on the aromatic ring were studied by electron ionisation mass spectrometry (EIMS). It was deduced that the compounds 1–3 are converted into the tautomeric 4-(arylimino)pentan-2-one during the EI process. Mass spectrometric decompositions of ortho-substituted derivatives (1 and 4) were found to be different from those observed for meta- and para-isomers. The fragmentation pathways are discussed on the basis of data from linked B/E and B2/E scans, mass-analysed ion kinetic energy (MIKE) spectra, accurate mass measurements and isotope labelling.
Electron Ionization Mass Spectra and Their Reproducibility for Trialkylsilylated Derivatives of Organic Acids, Sugars and Alcohols
Authors: Sobolevsky Tim G. , Chernetsova Elena S. , Revelsky Alexander I. , Revelsky Igor A. , Starostin Alexander B. , Miller Barbara , Oriedo Vincent
Published: November 2003

Mass spectra of trialkylsilyl derivatives of fatty acids, dicarboxylic acids, hydroxyacids, oxoacids, sugars, amino acids and alcohols were obtained. Amino acids were analyzed as tert-butyldimethylsilyl derivatives; all other model compounds were analyzed as trimethylsilyl derivatives. Reproducibility of the electron ionization (EI) mass spectra for the derivatives obtained was discussed. It was shown that, for many investigated derivatives, composition of the respective mass spectra depended greatly on ion source contamination. The trimethylsilylated α-tocopherol mass spectrum composition was most significantly influenced by ion source contamination. This compound can be used to test ion source contamination.
An Empirical Analysis of Firms' Product Line Decisions
Authors: Putsis William P. , Bayus Barry L.
Published: November 2003

Despite the importance of product line management as a competitive tool, empirical research addressing the determinants of firm product line decisions is sparse. In this article, the authors propose and empirically estimate a descriptive model of firm product line decisions in the personal computer industry over the period 1981-92. The model incorporates the firm's initial choice of the direction of a product line change (i.e., the product line can be expanded, contracted, or maintained) and the conditional choice related to the magnitude of any product line change (i.e., how many products to introduce or withdraw). The authors show that there are important substantive insights to be gained by analyzing the product line decision in this fashion. In the personal computer industry, for example, firms expand their product lines when industry barriers are low or market opportunities are perceived to exist. High market share firms aggressively expand their product lines, as do firms with relatively high prices or short product lines. In general, the results highlight the various internal and external factors that influence firms' management of their product lines.
Entrenched Knowledge Structures and Consumer Response to New Products
Authors: Moreau C. Page , Lehmann Donald R. , Markman Arthur B.
Published: November 2003

Although diffusion models have been successfully used to predict the adoption patterns of new products and technologies, little research has examined the psychological processes underlying the individual consumer's adoption decision. This research uses the knowledge transfer paradigm, studied often in the context of analogies, to demonstrate that both existing knowledge and innovation continuity are major factors influencing the consumer's adoption process. In two experiments, the authors demonstrate that the relationship between expertise and adoption is relatively complex. Specifically, their findings indicate that, compared with novices, experts report higher comprehension, more net benefits, and therefore higher preferences for continuous innovations. However, for discontinuous innovations, experts' entrenched knowledge is related to lower comprehension, fewer perceived net benefits, and lower preferences compared with that of novices. Only when this entrenched knowledge is accompanied by relevant information from a supplementary knowledge base are experts able to understand and appreciate discontinuous innovations. These findings have implications for segmentation, media planning, and the creation of product/brand loyalty.
Remote Purchase Environments: The Influence of Return Policy Leniency on Two-Stage Decision Processes
Authors: Wood Stacy L.
Published: November 2003

The growth of catalog sales and the enormous potential of e-commerce elevates the importance of understanding remote purchase. Remote purchase environments differ from traditional bricks-and-mortar purchases in that the purchase decision is more likely to be framed as two separate decisions: consumers' decisions to order and, upon receipt, their decisions to keep or return the item. These two decisions are separated by a period of time, and crucial experiential information often is available only at the second decision point (i.e., after receipt). Consumers' initial lack of experiential information makes product choice more risky. Return policy leniency is one way to minimize the inherent consumer risk, but retailers may avoid instituting overtly lenient policies because they expect increased return rates. However, the endowment effect suggests some surprising benefits of return policy leniency to the retailer. Results from three experiments provide support for the idea that product ownership depends more on perception than possession.
Does Doing Good Always Lead to Doing Better? Consumer Reactions to Corporate Social Responsibility
Authors: Sen Sankar , Bhattacharya C.B.
Published: November 2003

In the face of marketplace polls that attest to the increasing influence of corporate social responsibility (CSR) on consumers' purchase behavior, this article examines when, how, and for whom specific CSR initiatives work. The findings implicate both company-specific factors, such as the CSR issues a company chooses to focus on and the quality of its products, and individual-specific factors, such as consumers' personal support for the CSR issues and their general beliefs about CSR, as key moderators of consumers' responses to CSR. The results also highlight the mediating role of consumers' perceptions of congruence between their own characters and that of the company in their reactions to its CSR initiatives. More specifically, the authors find that CSR initiatives can, under certain conditions, decrease consumers' intentions to buy a company's products.
First observation of homozygous hemoglobin hamadan (B 56 (D7) GLY‐ARG) and beta thalassemia (‐29 G>A)‐ hemoglobin Hamadan combination in a Turkish family
Authors: Akar Ece , Özdemir Sibel , Hakki Timur Ismail , Akar Nejat
Published: November 2003

During screening surveys for beta thalassemia and abnormal hemoglobins in Mugla, a city located in the Aegean Region of Turkey, a hemoglobin variant was detected in two large families residing in two neigboring cities (i.e., Muğla and Aydin) without any clinical signs. Further analysis of the variant revealed it as Hb Hamadan (B 56 (D7) GLY‐ARG). Family screening revealed the father of the propositus as homozygote Hb Hamadan. The grandfather of the index case was detected as combination of Hb Hamadan with beta thalassemia. The beta thalassemia carrier had a promotor mutation at −29 G>A, which is also a novel mutation. Furthermore, we described a simple and rapid restriction enzyme digestion protocol (Hha I) for the verification of Hb Hamadan. The clinical and hematologic data of the index case and his father showed that neither homozygous Hb Hamadan nor combination with beta thalassemia has clinical importance. This is also important especially from the prenatal diagnosis point of view. Am. J. Hematol. 74:280–282, 2003. © 2003 Wiley‐Liss, Inc.
Successful treatment of acquired pure red cell aplasia (PRCA) by allogeneic peripheral blood stem cell transplantation
Authors: Tseng Shih‐Bin , Lin Sheng‐Fung , Chang Chao‐Sung , Liu Ta‐Chih , Hsiao Hui‐Hua , Liu Yi‐Chang , Tsai Hui‐Jen , Chen Tyen‐Po
Published: November 2003

A 37‐year‐old male was treated successfully by peripheral blood stem cell transplantation (PBSCT) from his HLA‐identical sister for refractory acquired pure red cell aplasia (PRCA). The conditioning regimen was cyclophosphamide 50 mg/kg/day for 4 days plus TBI 300 cGy in a single fraction. Absolute neutrophil count (ANC) >500/μl and platelet counts >20,000/μl were achieved 8 days after PBSCT without transfusion. Chimerism study on day 218 revealed full donor chimerism. The hemoglobin level was stable around 12–13 g/dl with normal leukocyte and platelet counts after PBSCT during a long follow‐up period. From this case, PBSCT should be considered for patients with refractory acquired PRCA with an HLA‐identical donor. Am. J. Hematol. 74:273–275, 2003. © 2003 Wiley‐Liss, Inc.
Identification of hemochromatosis gene polymorphisms in chronically transfused patients with sickle cell disease
Authors: Jeng Michael R. , Adams‐Graves Patricia , Howard Thad A. , Whorton Matthew R. , Li Chin‐Shang , Ware Russell E.
Published: November 2003

Three polymorphic gene mutations in the human hemochromatosis (HFE) gene (C282Y, H63D, S65C) are associated with non‐transfusion–related iron overload in Caucasians. More recently, these mutations have also been identified in African‐Americans. However, the prevalence of HFE gene mutations in African‐Americans with sickle cell disease (SCD) has not been described. The presence of these mutations in this population is particularly important, because patients with SCD may be placed on chronic red cell transfusion therapy and are thus at further risk for iron overload. Thus, we attempted to establish the gene mutation prevalence in African‐Americans with SCD, to compare this frequency with published gene frequencies in African‐Americans, and to evaluate their significance with regard to transfusion‐related iron overload. Eighty‐nine African‐American patients with SCD, all of whom were receiving chronic red cell transfusion therapy, were screened by DNA analysis for the three HFE gene mutations. Two patients were heterozygous for the C282Y HFE mutation (2.3%), six were heterozygous for the H63D mutation (6.8%), none carried the S65C mutation (0.0%), and no homozygous or compound heterozygous subjects were identified. The prevalence of C282Y and H63D in the SCD population was similar to that observed in the general African‐American population. In addition, there was no increased mutation prevalence when comparing those SCD patients on chronic transfusion therapy who had ferritin levels greater than 2,500 ng/mL and those less than 2,500 ng/mL. This study represents the first identification of the known HFE gene mutations by DNA analysis in the SCD population. We conclude that the presence of recognized HFE coding region mutations do not seem to have an impact on the degree of iron overload in patients with SCD receiving chronic transfusion therapy. Am J. Hematol. 74:243–248, 2003. © 2003 Wiley‐Liss, Inc.
Non‐Hodgkin's lymphoma, leukemia, and exposures in agriculture: Results from the Italian multicenter case‐control study
Authors: Miligi Lucia , Costantini Adele Seniori , Bolejack Vanessa , Veraldi Angela , Benvenuti Alessandra , Nanni Oriana , Ramazzotti Valerio , Tumino Rosario , Stagnaro Emanuele , Rodella Stefania , Fontana Arabella , Vindigni Carla , Vineis Paolo
Published: November 2003

Background

The etiology of non‐Hodgkin's lymphoma (NHL) and leukemia is still largely unknown, but exposure to chemicals, in particular pesticides, has been suggested to be a risk factor.

Methods

A large population‐based case‐control study was conducted in Italy with the aim of investigating the associations between pesticide exposure and NHL, and solvents and leukemia. Data presented in this article refer to 1,575 interviewed cases and 1,232 controls in the nine agricultural study areas.

Results

Exposure to nitro‐derivatives and phenylimides among fungicides, hydrocarbon derivatives and insecticide oils among insecticides, and the herbicide amides are the chemical classes observed to be associated with the pathologies under investigation.

Conclusions

The results of the case‐control study suggest an increased risk for NHL and leukemia, and some chemical classes of pesticides, although few are statistically significant and some are based on few exposed cases. The results also show that men and women experience both similar and different risks for the same environmental agricultural exposures. Am. J. Ind. Med. 44:627–636, 2003. © 2003 Wiley‐Liss, Inc.
The incidence of respiratory symptoms in female Swedish hairdressers
Authors: Brisman Jonas , Albin Maria , Rylander Lars , Mikoczy Zoli , Lillienberg Linnéa , Höglund Anna Dahlman , Torén Kjell , Meding Birgitta , Diab Kerstin Kronholm , Nielsen Jørn
Published: November 2003

Background

Airway diseases in hairdressers are a concern. The objective of this investigation is to evaluate the risk for three respiratory symptoms, wheeze, dry cough, and nasal blockage, in hairdressers.

Methods

A questionnaire on respiratory symptoms, atopy, smoking, and work history was answered by 3,957 female hairdressers and 4,905 women from the general population as referents. Incidence rates (IR) and incidence rate ratios (IRRs) for the three symptoms were estimated.

Results

The IRs of all three studied symptoms were higher in the hairdressers compared with the referents. Smoking modified the effects of cohort affiliation for all three symptoms; the combined effect from hairdressing work and smoking was less than expected. In addition, the effect of cohort affiliation for wheeze was also modified by atopy, and the effect of cohort affiliation for nasal blockage was also modified by calendar year.

Conclusions

Hairdressing work was associated with increased incidences of respiratory symptoms. Smoking had a negative modifying effect. Am. J. Ind. Med. 44:673–678, 2003. © 2003 Wiley‐Liss, Inc.
Cancer incidence among laboratory workers in biomedical research and routine laboratories in Israel: Part II–nested case‐control study
Authors: Shaham Judith , Gurvich Rachel , Kneshet Yael
Published: November 2003

Background

A case‐control study nested within a cohort study of biomedical laboratory workers was conducted to examine whether the excess cancer morbidity that we found can be explained by exposure to a particular group of substances, taking into consideration potential confounders.

Methods

The study population included 163 cases and two matched control groups: laboratory workers (311) and general population (448) workers.

Results

Multiple conditional regression analysis showed that working in research laboratories involved an increased risk of cancer generally among women [risk ratio 2.2 (1.2–4.3)], and of breast cancer particularly [risk ratio 2.3 (1.1–4.7). Seventy‐six percent (76%) of breast, 87% of thyroid, 60% of ovary and prostate, 94% of melanoma, and 50% of leukemia cases were ever exposed to at least one known human carcinogen.

Conclusion

Our results exclude the possibility that the excess cancer morbidity was related to personal risk factors but they may be explained by exposure factors. Am. J. Ind. Med. 44:611–626, 2003. © 2003 Wiley‐Liss, Inc.
Synapse signalling complexes and networks: machines underlying cognition
Authors: Grant Seth G.N.
Published: November 2003

All thoughts and actions are encoded in patterns of neuronal electrical activity. Circuits of nerve cells connected by synapses are dedicated to processing information in these patterns. Information is not only transmitted across the synapse but also monitored by postsynaptic molecular machines. These machines are macromolecular complexes of ∼100 proteins organised into a network of protein interactions. The network can be mathematically described as a scale‐free network. Components of the complexes are necessary for decoding the neural code and converting electrical information into biochemical changes. The network properties of these complexes may explain many of the features of neuronal plasticity and cognitive function in rodents. Importantly, these multiprotein complexes and their network properties shed new light on the basis of human cognitive diseases including schizophrenia, autism, Huntington's disease and mental retardation. Supplementary material for this article can be found on the BioEssays website http://www.interscience.wiley.com/jpages/0265‐9247/suppmat/index.html. BioEssays 25:1229–1235, 2003. ©2003, Wiley Periodicals Inc.
The Dirichlet problem for the minimal surface system in arbitrary dimensions and codimensions
Authors: Wang Mu‐Tao
Published: November 2003

Let Ω be a bounded C2 domain in ℝn and ϕ ∂Ω → ℝm be a continuous map. The Dirichlet problem for the minimal surface system asks whether there exists a Lipschitz map f : Ω → ℝm with f|∂Ω = ϕ and with the graph of f a minimal submanifold in ℝn+m. For m = 1, the Dirichlet problem was solved more than 30 years ago by Jenkins and Serrin [12] for any mean convex domains and the solutions are all smooth. This paper considers the Dirichlet problem for convex domains in arbitrary codimension m. We prove that if ψ : ¯Ω → ℝm satisfies 8nδ supΩ |D2ψ| + √2 sup∂Ω |Dψ| < 1, then the Dirichlet problem for ψ|∂Ω is solvable in smooth maps. Here δ is the diameter of Ω. Such a condition is necessary in view of an example of Lawson and Osserman [13]. In order to prove this result, we study the associated parabolic system and solve the Cauchy‐Dirichlet problem with ψ as initial data. © 2003 Wiley Periodicals, Inc.
Runx2/Cbfa1 stimulation by retinoic acid is potentiated by BMP2 signaling through interaction with Smad1 on the collagen X promoter in chondrocytes
Authors: Drissi M. Hicham , Li Xufeng , Sheu Tzong J. , Zuscik Michael J. , Schwarz Edward M. , Puzas J. Edward , Rosier Randy N. , O'Keefe Regis J.
Published: November 2003

Chondrocyte differentiation is a fundamental process during endochondral ossification. Several factors regulate maturation via the activity of downstream signaling pathways that target specific transcription factors and regulate chondrocyte‐specific genes. In this study, we investigated the mechanisms involved in the regulation of chick lower sternal chondrocyte maturation upon stimulation by retinoic acid (RA) and the bone morphogenetic protein BMP2. RA‐induced Runx2 in lower sternal chondrocyte cultures and over‐expression of wild‐type (WT) Runx2 enhanced colX and alkaline phosphatase activity, while over‐expression of dominant negative Runx2 was inhibitory. Furthermore, WT Runx2 enhanced the effects of both BMP2 and RA on colX expression, while the effects of both growth factors were completely blocked in cultures over‐expressing dominant negative Runx2. Similarly, WT Runx2 enhanced the induction of colX by Smad1. Smad1 and Runx2 were found to act cooperatively at the chicken type X collagen promoter and elimination of either the putative Smad binding site or Runx2 binding site eliminated responsiveness to BMP2, RA, or either of the transcription factors. Altogether the results show cross talk between the BMP‐associated Smads and Runx2 during chondrocyte differentiation and dependence upon both signals for induction of the type X collagen promoter. Factors or signals that alter either of these transcription factors regulate the rate of chondrocyte differentiation. © 2003 Wiley‐Liss, Inc.
BMP treatment of C3H10T1/2 mesenchymal stem cells induces both chondrogenesis and osteogenesis
Authors: Shea Colleen M. , Edgar Cory M. , Einhorn Thomas A. , Gerstenfeld Louis C.
Published: November 2003

The molecular mechanisms by which bone morphogenetic proteins (BMPs) promote skeletal cell differentiation were investigated in the murine mesenchymal stem cell line C3H10T1/2. Both BMP‐7 and BMP‐2 induced C3H10T1/2 cells to undergo a sequential pattern of chondrogenic followed by osteogenic differentiation that was dependent on both the concentration and the continuous presence of BMP in the growth media. Differentiation was determined by the expression of chondrogenesis and osteogenesis associated matrix genes. Subsequent experiments using BMP‐7 demonstrated that withdrawal of BMP from the growth media led to a complete loss of skeletal cell differentiation accompanied by adipogenic differentiation of these cells. Continuous treatment with BMP‐7 increased the expression of Sox9, Msx 2, and c‐fos during the periods of chondrogenic differentiation after which point their expression decreased. In contrast, Dlx 5 expression was induced by BMP‐7 treatment and remained elevated throughout the time‐course of skeletal cell differentiation. Runx2/Cbfa1 was not detected by ribonuclease protection assay (RPA) and did not appear to be induced by BMP‐7. The sequential nature of differentiation of chondrocytic and osteoblastic cells and the necessity for continuous BMP treatment to maintain skeletal cell differentiation suggests that the maintenance of selective differentiation of the two skeletal cell lineages might be dependent on BMP‐7‐regulated expression of other morphogenetic factors. An examination of the expression of Wnt, transforming growth factor‐β (TGF‐β), and the hedgehog family of morphogens showed that Wnt 5b, Wnt 11, BMP‐4, growth and differentiation factor‐1 (GDF‐1), Sonic hedgehog (Shh), and Indian hedgehog (Ihh) were endogenously expressed by C3H10T1/2 cells. Wnt 11, BMP‐4, and GDF‐1 expression were inhibited by BMP‐7 treatment in a dose‐dependent manner while Wnt 5b and Shh were selectively induced by BMP‐7 during the period of chondrogenic differentiation. Ihh expression also showed induction by BMP‐7 treatment, however, the period of maximal expression was during the later time‐points, corresponding to osteogenic differentiation. An interesting phenomenon was that BMP‐7 activity could be further enhanced twofold by growing the cells in a more nutrient‐rich media. In summary, the murine mesenchymal stem cell line C3H10T1/2 was induced to follow an endochondral sequence of chondrogenic and osteogenic differentiation dependent on both dose and continual presence of BMP‐7 and enhanced by a nutrient‐rich media. Our preliminary results suggest that the induction of osteogenesis is dependent on the secondary regulation of factors that control osteogenesis through an autocrine mechanism. © 2003 Wiley‐Liss, Inc.
Prevalence of selective inhibition of HPV‐16 DNA amplification in cervicovaginal lavages
Authors: Lefevre Jonas , Hankins Catherine , Pourreaux Karina , Voyer Hélène ,   The Canadian Women's HIV Study Group, Coutlée François
Published: November 2003

HPV‐16 viral load has been assessed with real‐time PCR assays by measuring HPV‐16 DNA and a human gene in genital samples. HPV‐16 viral load measurements are thus based on the inference that inhibitors contained in samples will equally impede amplification of DNA sequences from HPV‐16 and human DNA. We have previously shown that sample lysates can inhibit amplification of HPV‐16 but not β‐globin DNA. In the current study, cervicovaginal lavages lysates considered adequate for PCR analysis by a qualitative β‐globin PCR test, were screened for the presence of inhibitors using internal controls (IC) for HPV‐16 DNA and β‐globin in real‐time PCR assays. Of 150 lysates screened with both ICs, 12 (8%) contained inhibitors. Inhibition of amplification of both ICs was demonstrated in four of these specimens. In eight lysates, amplification of HPV‐16 IC only was impeded. Six (50%) of these 12 lysates tested positive for HPV‐16 DNA despite the presence of PCR inhibitors. The HPV‐16 viral load increased significantly after dilution of 11 of 12 lysates, demonstrating the presence of inhibitors in the undiluted lysate. Nine (90%) of 10 samples with inhibitors that were tested after dilution did not demonstrate inhibitory activity. The use of internal controls in real‐time PCR is clearly essential to determine HPV viral loads since the effect of inhibitors on primer‐driven genomic amplification is variable. J. Med. Virol. 72:132–137, 2004. © 2004 Wiley‐Liss, Inc.
HLA phenotypes and outcomes of hepatitis B virus infection in Taiwan
Authors: Wu Ya‐Fang , Wang Li‐Yu , Lee Tsung‐Dao , Lin Hans Hsienhong , Hu Chi‐Tan , Cheng Mu‐Liang , Lo Shih‐Yen
Published: November 2003

The relationship of HLA phenotype and outcome of hepatitis B virus (HBV) infection was studied in two ethnic groups of Taiwan: Han Chinese and Taiwanese Aborigines. In Han Chinese, the study groups consisted of 98 persons who tested both hepatitis B surface antigen (HBsAg) and anti‐HBs negative (Uninfected Group), 324 persons who tested HBsAg negative and both anti‐HBs and anti‐HBc positive (Recovered Group), and 98 patients who tested HBsAg positive for at least 6 months (Chronically Infected Group). In Taiwanese Aborigines, the study groups consisted of 34 persons in Uninfected Group, 229 persons in the Recovered Group, and 138 patients in the Chronically Infected Group. All subjects were tested for HLA (A, B, DRB1) phenotypes by sequence‐specific oligonucleotide probe hybridization (SSOPH). HLA‐DR*0406 was significantly more frequent in the Recovered Group, compared with the Chronically Infected Group (P < 0.001) in Han Chinese. There was a significant excess of HLA‐B*4001 (P = 0.045) in the Recovered Group, compared with the Chronically Infected Group in Taiwanese Aborigines. The observation that different HLA phenotypes associated with recovery from HBV infection in different racial groups implies that various HLA molecules could present different HBV epitopes to induce effective immune responses. J. Med. Virol. 72:17–25, 2004. © 2004 Wiley‐Liss, Inc.
Mild carbon monoxide exposure impairs the developing auditory system of the rat
Authors: Webber Douglas S. , Korsak Rose A. , Sininger Lauren K. , Sampogna Sharon L. , Edmond John
Published: November 2003

The object of this study was to determine if chronic exposure to mild concentrations of CO in air caused changes in the integrity of the inferior colliculus during the most active period of synaptogenesis/auditory development. We examined all subregions of the inferior colliculus (IC) of rats by immunocytochemical approaches after pups were exposed chronically to CO concentrations of, 0, 12.5, 25, and 50 ppm in air starting at Day 8 through 20–22 days of age. Mother‐reared pups were compared to the gastrostomy‐reared pups with or without CO exposure for basal neural activity, using c‐Fos immunoreactivity as a marker. Half the rats were examined at 27 days of age, 5 days after the end of CO exposure, and the other half were examined 50 days later at 75–77 days of age. In the central nucleus of the IC, the number of cells expressing a basal level of c‐Fos was decreased significantly in the CO‐exposed animals when compared to controls; however, there was little or no difference in the number of cells expressing c‐Fos in the other subregions of the IC. We conclude that the central nucleus of the inferior colliculus is affected selectively by mild CO exposure (0.0012% in air) and that this reduction in neuronal activity persists into adulthood. © 2003 Wiley‐Liss, Inc.