bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic calibration method of adaptive array with linear array utilizing signal circulation among antennas (ACT‐FL)
Authors: Nishimori Kentaro , Cho Keizo , Hori Toshikazu
Published: July 2004

An adaptive array for a frequency division duplex (FDD) system requires calibration among the antennas, the cables, and the transmitters and receivers to form the desired transmission directivity. In this paper, we propose the Automatic Calibration method of adaptive array using Transmitting signals for FDD systems with Linear array (ACT‐FL) by using the signal circulation among the antennas and not using any additional elements or external information for calibrating the antennas and cables. By studying the calibration accuracy of the ACT‐FL through analysis and tests including the mutual coupling of the antennas, we explain the applicable element spacing and the beam width in ACT‐FL. We also evaluate the signal‐to‐interference power ratio (SIR) at the interference arrival time from radiation pattern measurements by using a testbed implementing ACT‐FL and demonstrate the effectiveness of ACT‐FL. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(8): 20–31, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20105
Computational error in FDTD analysis of short dipole antenna and its reduction technique
Authors: Pongpaibool Pornanong , Uno Toru , Sato Hiroyuki
Published: July 2004

Finite difference time domain (FDTD) methods have been applied to complex models mixing dielectrics and conductors because model development is simple and a practical level of accuracy is easily obtained. However, to correctly determine the impedance of a linear antenna, the cell size must be extremely small regardless of the structure's simplicity. The reason is believed to be the inability to model the rapidly fluctuating electromagnetic field near the antenna conductor electrode. In this paper, we explain the causes of several errors of FDTD methods, and propose a method that reduces the errors in the FDTD calculation by incorporating the spatial distribution of the quasi‐static approximation of the electromagnetic field into the FDTD cells and improves the accuracy without using an extremely small cell size. In addition, we compare the proposed method to the results of the Galerkin moment method and demonstrate its effectiveness. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(8): 32–40, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20106
Autocorrelation associative memory using refractory period of neurons
Authors: Oda Mikio , Miyajima Hiromi
Published: July 2004

In autocorrelation associative memory, a monotonic activation function is used from the viewpoint of network stability. The problems arise that the memory capacity is reduced and false memory can be generated, although the structure is simplified. This paper proposes a new memory model in which the associative ability is improved, while the conventional monotonic activation function is used in the autocorrelation associative memory model. In the proposed model, the refractory period is defined in the neuron, and the same convergence of the network as in the Hopfield model is always guaranteed. In the case of the discrete‐time model, the proposed model with the refractory period T = 1 is equivalent to the case of a ternary nonmonotonic activation function. In other words, the proposed model can be regarded as a model including the nonmonotonic activation function model. The following results are shown by numerical experiment. As a discrete‐time discrete‐value model, the proposed model has a higher associative ability than the Hopfield model. As a continuous‐time continuous‐value model, when the refractory period is long, the associative ability is greater than that of the Hopfield model guaranteeing the same convergence. When the refractory period is short, the associative ability is further improved. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(8): 41–52, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20107
A two‐level ALife system with predator
Authors: Satoh Taiji , Mizukami Yoshiki , Tanaka Kanya , Nara Koichi
Published: July 2004

This paper proposes a method of deriving a global solution for a nonlinear optimization problem with a multipeak function as the objective function. When the objective function in the nonlinear optimization problem is differentiable, a gradient method such as the quasi‐Newton method can be used to derive the solution with high speed. When the function is multipeaked, however, there is a high probability that the procedure may fall in a local solution. Methods that can derive a global solution for a multipeaked function without using a gradient include simulated annealing (SA) and tree annealing (TA), in which the probability of arriving at a global solution is increased by including probabilistic operations in the mechanism of search for the solution. A problem in these methods, however, is that considerable computation time is required. In this study, artificial life (ALife) is implemented on a computer in order to realize global optimization by a distributed optimization technique. Nonlinear optimization is considered, the ALife technique is extended to a multidimensional continuous system, and an evaluation function is proposed so that emergent colonization is generated in a promising area including the global solution. In this study, a predator is introduced in order to reduce the time until the emergent colonization is generated. This situation is supported by a rapid decrease in the variation of the Artorg, which is a form of ALife. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(8): 53–60, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20108
Robust simultaneous registration of multiple range images comprising a large number of points
Authors: Nishino Ko , Ikeuchi Katsushi
Published: July 2004

As part of a project for the electronic preservation of cultural objects, this paper proposes a new technique for position alignment of multiple range images. In particular, the study focuses on accuracy of alignment and robustness to noise in the input data. Using the conjugate gradient method based on the M‐estimator, simultaneous alignment is performed by minimization of an error function that handles all range images at the same time. Furthermore, for more efficient and more accurate search for matching points, the KD‐tree data structure is utilized, and additional attributes such as the laser reflection brightness and the brightness of the three‐dimensional point itself are introduced into the error measure. This paper proposes such a method and presents the results of experiments with real data. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(8): 61–74, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20109
A continuous‐flow instrument for the determination of linear polyacrylamide stability
Authors: Klepárník Karel , Mikuška Pavel
Published: July 2004

Alkaline hydrolysis of high‐molecular‐mass (10 MDa) linear polyacrylamide, a widely used replaceable sieving medium for the capillary electrophoresis of DNA fragments and proteins, was investigated. The release rate of ammonia, a product of amide group hydrolysis, was monitored by a high‐sensitivity continuous‐flow system. The experimental results show a rapid onset of hydrolysis at a temperature of 70°C. While the degree of 1 h hydrolysis was evaluated to reach about 16% at 70°C and pH 13, it drops to 5% at 50°C and pH 12.5.
Simulation of the seismic performance of the Bolu Viaduct subjected to near‐fault ground motions
Authors: Park S. W. , Ghasemi H. , Shen J. , Somerville P. G. , Yen W. P. , Yashinsky M.
Published: July 2004

The seismic performance of the Bolu Viaduct in the Duzce, Turkey, earthquake of November 1999 was studied via a non‐linear, time‐history analysis of a multi‐degree of freedom model. The viaduct had a seismic isolation system consisting of yielding‐steel energy dissipation units and sliding pot bearings. The Duzce earthquake caused a surface rupture across the viaduct, which resulted in excessive superstructure movement and widespread failure of the seismic isolation system. The effect of the rupture was modeled by a static, differential ground displacement in the fault‐parallel direction across the rupture. The ground motions used in the analysis contain common near‐fault features including a directivity pulse in the fault‐normal direction and a fling step in the fault‐parallel direction. The analysis used a finite element package capable of modeling the mechanical behavior of the seismic isolation system and focused on the structural response of a 10‐span module of the viaduct. This analysis showed that the displacement of the superstructure relative to the piers exceeded the capacity of the bearings at an early stage of the earthquake, causing damage to the bearings as well as to the energy dissipation units. The analysis also indicated that shear keys, both longitudinal and transverse, played a critical role in preventing collapse of the deck spans. Published in 2004 by John Wiley & Sons, Ltd.
Response of a double‐wedge base‐isolation device
Authors: Enrique Luco J.
Published: July 2004

A novel base‐isolation device is described and its performance is compared with that of a friction pendulum bearing. In its simplest form, the device consists of two wedges sliding on a horizontal plane in opposite directions and constrained from retreating by ratchets or bilinear dampers. The superstructure rests at the intersection of the two wedges. For a sufficiently large horizontal acceleration of the base, the structure starts to move up the inclined plane of one of the wedges, which remains fixed while the second wedge is slaved to follow the structure. As the direction of the base acceleration reverses, the process is reversed and the structure starts to climb on the second inclined plane while the first wedge follows. The overall result is that the horizontal acceleration of the structure is reduced with respect to that of the base and that kinetic energy associated with horizontal velocities is systematically transformed into potential energy. In the case of motion in a vertical plane, the device has the following advantages over a friction pendulum: (i) the sliding surface is linear instead of curved, (ii) kinetic energy is systematically transformed into potential energy during the strong ground motion, and (iii) the device is slowly self‐centering. Copyright © 2004 John Wiley & Sons, Ltd.
Semi‐empirical model for site effects on acceleration time histories at soft‐soil sites. Part 2: calibration
Authors: Bárcena Armando , Esteva Luis
Published: July 2004

A previously developed simplified model of ground motion amplification is applied to the simulation of acceleration time histories at several soft‐soil sites in the Valley of Mexico, on the basis of the corresponding records on firm ground. The main objective is to assess the ability of the model to reproduce characteristics such as effective duration, frequency content and instantaneous intensity. The model is based on the identification of a number of parameters that characterize the complex firm‐ground to soft‐soil transfer function, and on the adjustment of these parameters in order to account for non‐linear soil behavior. Once the adjusted model parameters are introduced, the statistical properties of the simulated and the recorded ground motions agree reasonably well. For the sites and for the seismic events considered in this study, it is concluded that non‐linear soil behavior may have a significant effect on the amplification of ground motion. The non‐linear soil behavior significantly affects the effective ground motion duration for the components with the higher intensities, but it does not have any noticeable influence on the lengthening of the dominant ground period. Copyright © 2004 John Wiley & Sons, Ltd.
The successful use of maggots in necrotizing fasciitis of the neck: A case report
Authors: Preuss Simon F. , Stenzel Mark J. , Esriti Anwar
Published: July 2004

Background.

The use of maggots to digest necrotic tissue as a form of wound debridement has a long history in medicine. Necrotizing fasciitis of the neck has a high mortality rate despite aggressive surgical and medical intervention. The use of maggots in this disease has been reported only once before.

Methods.

We report the case of a 73‐year‐old woman, who underwent neck dissection and had necrotizing fasciitis of the neck develop shortly after. After initial surgical wound debridement, we used maggots as a biosurgical method for further debridement. A net containing 100 maggots (Biobag; BioMonde, Germany) was used.

Results.

Daily wound dressing showed rapid improvement of the wound; 4 days after beginning treatment, the wound was free of necroses.

Conclusion.

In this case, we could avoid repeated surgical wound debridement with the use of sterile maggots. The frequently rapid progression of necrotizing fasciitis could be well controlled. © 2004 Wiley Periodicals, Inc. Head Neck 26: 747–750, 2004
Immunotherapy using autologous monocyte‐derived dendritic cells pulsed with leukemic cell lysates for acute myeloid leukemia relapse after autologous peripheral blood stem cell transplantation
Authors: Lee Je‐Jung , Kook Hoon , Park Myong‐Suk , Nam Jong‐Hee , Choi Bo‐Hwa , Song Won‐Hyun , Park Kyeong‐Soo , Lee Il‐Kwon , Chung Ik‐Joo , Hwang Tai‐Ju , Kim Hyeoung‐Joon
Published: July 2004

Although a second stem cell transplantation (SCT) can be used as salvage therapy in patients with relapsing leukemia after SCT, most of these patients have a poor outcome. We tried clinical vaccination using monocyte‐derived dendritic cells (DCs) pulsed with leukemic lysates to treat relapsing acute myeloid leukemia (AML) after autologous SCT. To generate DCs, CD14+ cells isolated from peripheral blood stem cell products were cultured in AIM‐V in the presence of GM‐CSF and IL‐4. Adding TNF‐α on day 6 induced maturation of the DCs, which were harvested on day 8 or 9. The DCs were incubated with tumor lysate and KLH for 2 hr at 37°C. After certifying the absence of microorganisms and endotoxins, the patients received four DC vaccinations at two‐ to three‐week intervals. Two patients received four DC vaccinations with means of 7.8 × 106 and 9 × 106 DCs at two‐ to three‐week intervals. The DC vaccinations were well tolerated with no apparent side effects. After the vaccinations, the patients showed immunological responses with positive delayed‐type hypersensitivity skin reaction and increasing autologous T cells stimulatory capacity to the DCs; however, the BM blast percentage of the patients did not improve. The results suggest that DCs are a feasible cellular therapy for relapsing AML after autologous SCT. J Clin Apheresis 19:66–70, 2004. © 2004 Wiley‐Liss, Inc.
Improved treatment of sudden hearing loss by specific fibrinogen aphaeresis
Authors: Ullrich Heidrun , Kleinjung Tobias , Steffens Thomas , Jacob Peter , Schmitz Gerd , Strutz Jürgen
Published: July 2004

The etiology of sudden sensorineural hearing loss is still unclear and is thought to result from disturbances of microcirculation, infectious causes, or autoimmune disorders. So far standard therapy did not show clear improvement over spontaneous remission rate, which is assumed to be about 50% [Nakashima et al., Acta. Otolaryngol. Stockh. 514:14–16, 1994; Schuknecht and Donovan, Arch. Otorhinolaryngol. 243:1–15, 1986; Harris and Sharp, Laryngoscope 100:516–524, 1990; Mayot et al., Clin. Immunol. Immunopath. 68:41–45, 1993; Gussen, Ann. Otol. Rhinol. Laryngol. 85:94–100, 1976]. Elevated blood viscosity due to high fibrinogen levels is supposed to cause decreased cochlear blood flow and thus initiate sudden hearing loss. The specific lowering of fibrinogen immediately decreases plasma viscosity exactly to the desired extent and should lead to improved cochlear blood flow [Suckfüll et al., Acta. Otolaryngol 119:763–766, 1999; Suckfüll, Lancet 360:1811–1817, 2002; Walch et al., Laryngol. Rhino. Otol. 75:641–645, 1996; Suckfüll et al., Otol. Neurotol. 23:309–311, 2002]. In a prospective uncontrolled pilot study on 36 patients with unilateral sudden onset sensorineural hearing loss (SHL) we tried to establish that 1–3 specific fibrinogen aphaereses alone improve recovery of hearing and that it is possible to lower fibrinogen to the target of 80–100 mg/dl without important side effects. Pure tone audiometry was carried out immediately before and after each aphaeresis as well as at 2 and 4 weeks and 6 months after treatment. Sixteen patients recovered spontaneously before undergoing fibrinogen adsorption. All 20 aphaeresis patients improved during immunoadsorption; in 60% of patients auditory thresholds returned to normal after the first immunoadsorption and treatment could be discontinued, in another 20% of patients complete recovery was reached after 4 weeks. The mean plasma fibrinogen concentration of the 20 patients before the first aphaeresis session was 308.1 ± 51.5 mg/dl. Immediately after the first treatment session, the fibrinogen concentration was lowered to 100.7 ± 25.3 mg/dl (P < 0.001). The second and third sessions also showed highly significant reductions in plasma fibrinogen. No important side effects were seen.In conclusion, specific fibrinogen adsorption is a promising new treatment modality that should be tested in a prospective, randomized controlled trial in patients with sudden hearing loss. J. Clin. Apheresis 19:71–78, 2004. © 2004 Wiley‐Liss, Inc.
Plasma exchange conditioning for ABO‐incompatible renal transplantation
Authors: Winters J.L. , Gloor J.M. , Pineda A.A. , Stegall M.D. , Moore S.B.
Published: July 2004

The supply of deceased donor kidneys is inadequate to meet demand. To expand the pool of potential donors, ABO‐incompatible transplants from living donors have been performed. We present the Mayo Clinic experience with such transplants. Enrollment was open to patients when the only available potential living kidney donor was ABO‐incompatible. Conditioning consisted of plasma exchanges followed by intravenous immunoglobulin. Splenectomy was performed at the time of transplant surgery. Post‐transplant immunosuppression consisted of anti‐T lymphocyte antibody, tacrolimus, mycophenolate mofetil, and prednisone. Isoagglutinin titers and scores were determined before and after each plasma exchange. Transplant outcomes were determined. Twenty‐six ABO‐incompatible transplants were performed. No hyperacute rejection occurred. Mean patient follow‐up was 400 days. Patient and graft survivals at last follow‐up were 92 and 85%, respectively. Antibody‐mediated rejection occurred in 46% and was apparently reversed in 83% by plasma exchange and increased immunosuppression. The initial plasma exchange reduced immediate spin and AHG hemagglutination reactivity scores by 53.5 and 34.6%, respectively. Over the course of the pretransplant plasma exchanges, the immediate spin and AHG hemagglutination reactivity scores decreased by 96.4 and 68.5%, respectively. At 3 and 12 months, the immediate spin and AHG hemagglutinin reactivity scores and titers were less than those at baseline but greater than or equal to those on the day of transplantation. Despite an increase in scores and titers, antibody‐mediated rejection was not present. Pre‐transplant plasma exchange conditioning combined with other immunosuppressives can be used to prepare patients for ABO‐incompatible kidney transplantation from living donors, but antibody‐mediated rejection post‐transplant is a common occurrence and allograft survival may be reduced. Controlled clinical trials are needed to identify the optimum conditioning for ABO‐incompatible renal transplants. J. Clin. Apheresis 19:79–85, 2004. © 2004 Wiley‐Liss, Inc.
Effect of different LDL‐apheresis methods on parameters involved in atherosclerosis
Authors: Hershcovici Tiberiu , Schechner Vered , Orlin Jerome , Harell Daniella , Beigel Yitzhak
Published: July 2004

LDL‐apheresis lowers the LDL level in patients with severe hypercholesterolemia. The present study compared three apheresis methods—DSA, DALI, and plasma exchange—for effectiveness in removal of LDL and effect on various blood parameters involved in atherogenesis. The study group included 6 patients with primary hypercholesterolemia unresponsive to maximal drug therapy. All were treated first with 4 consecutive plasma exchange sessions followed by 4 DSA sessions; in four out of six, an additional 4 sessions of DALI were then performed. Levels of lipoproteins, apoproteins, CRP, homocysteine, fibrinogen, and blood count were determined before and after each session. All 3 procedures yielded a significant reduction in total cholesterol and ApoB‐containing lipoproteins, with DALI being the most effective. Also, a significant reduction in triglycerides, HDL, and ApoA1 was observed with all the methods. The reduction in HDL‐C with DSA and DALI was greater than previously reported. The LDL/HDL‐cholesterol ratio decreased significantly with DSA and DALI and increased with plasma exchange. There was a significant decrease in CRP, fibrinogen, and platelets with all three methods, and a significant decrease in homocysteine only with DSA and DALI. All three procedures effectively reduced the concentration of various compounds involved in atherosclerosis. Plasma exchange is nonselective and cannot be recommended as the procedure of choice. J. Clin. Apheresis 19:90–97, 2004. © 2004 Wiley‐Liss, Inc.
Relapsed thrombotic thrombocytopenic purpura presenting as an acute cerebrovascular accident
Authors: Downes Katharine A. , Yomtovian Roslyn , Tsai H.M. , Silver Bernard , Rutherford Cynthia , Sarode Ravindra
Published: July 2004

Thrombotic thrombocytopenic purpura (TTP) is an uncommon but severe disorder that classically presents with microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and fluctuating neurological changes. Previously, it was impossible to make a diagnosis of TTP in the absence of thrombocytopenia or microangiopathic hemolysis (MAHA). We describe two cases of relapsing TTP that presented with acute cerebrovascular accident (CVA) without concurrent thrombocytopenia or MAHA after initial classical presentation of TTP. In both cases, the diagnosis of TTP as the cause of the CVA was attributed to severe deficiency of the von Willebrand factor cleaving protease, ADAMTS13 in plasma (11 and 12%, normal 79–127%). Each patient had a dramatic clinical improvement in response to therapeutic plasma exchange. The experience in these two cases suggests that TTP should be considered as a potential cause among patients presenting with a CVA, particularly if the patients have a history of TTP. J. Clin. Apheresis 19:86–89, 2004. © 2004 Wiley‐Liss, Inc.
L‐carnitine improves pH and decreases surface phosphatidylserine expression in extended stored apheresis platelets
Authors: Sweeney Joseph D. , Kouttab Nicola M. , Arduini Arduino
Published: July 2004

Extension of the storage period of apheresis platelets to seven or ten days may be possible with the implementation of screening for bacteria. This, however, may impair platelet quality, and additive compounds that improve storage parameters would be desirable. Apheresis platelets were harvested using the Cobe LRS device. Part of the product was aliquoted into two CLX® bags, 60 ml into each, on day 0. L‐carnitine (LC) to a final concentration of 5 mM was added to one container and saline to the other. pH, morphology score, and surface expression of phosphatidylserine were measured on day 1, and, in addition, hypotonic shock response (HSR) and the extent of shape change (ESC) on days 5, 10, and 13. Differences between test and controls were analyzed using paired t‐tests. The addition of LC improved pH by day 5, but was more evident by days 10 and 13. By day 10, significant differences (<0.01) were observed in pH (6.54 ± 0.3 vs. 6.75 ± 0.3), lactate (176 ± 31 vs. 150 ± 24 mg %), morphology score (213 ± 27 vs. 229 ± 35) and ESC (7 ± 6 vs. 11 ± 6). Percent surface phosphatidylserine expression was less in the LC treated platelets (16 ± 7 vs. 12 ± 4, P<0.03). Much of the benefit observed was attributable to improved parameters in some donors. LC improves the quality of extended stored apheresis platelets. J. Clin. Apheresis 19:98–102, 2004. © 2004 Wiley‐Liss, Inc.
Hematopoietic progenitor cell large volume leukapheresis (LVL) on the Fenwal Amicus blood separator
Authors: Burgstaler Edwin A. , Pineda Alvaro A. , Winters Jeffrey L.
Published: July 2004

A technique for large volume leukapheresis (LVL) for hematopoietic progenitor cell (HPC) collection using the Fenwal Amicus is presented. It was compared to standard collections (STD) with regard to CD34+ cell yields and cross‐cellular content. Optimal cycle volumes and machine settings were evaluated for LVL procedures. A total of 68 patients underwent 80 HPC collection procedures. Because of differences in CD34+ cell yields associated with peripheral white blood cell counts (WBC), the comparison was divided into groups of 20 with WBC ≤35 × 109/L (≤35 K) and those >35 × 109/L (>35 K). Baseline CD34+ cell counts (peripheral count when patient started HPC collection) were used (median 18–23 cells/μl). Significantly more whole blood (corrected for anticoagulant) was processed with LVL (LVL 20 l vs. STD 13.5 l). For ≤35 K, median CD34+ × 106, WBC × 109, RBC ml, Plt × 1011 yields/collection were 183, 21.2, 14, 0.8, respectively, for STD vs. 307, 22.1, 11, 1.0, respectively, for LVL. For >35 K, median CD34+ × 106, WBC × 109, RBC ml, Plt × 1011 yields/collection were 189, 32.7, 15, 1.4, respectively, for STD vs. 69, 40.8, 21, 1.3, respectively, for LVL. We have described a method of LVL using the Amicus that, in patients with pre‐procedure WBC ≤35×109/L, collects more CD34+ cells than a standard procedure with acceptable cross‐cellular content. This method is not recommended when pre‐procedure WBC counts are >35 × 109/L. J Clin Apheresis 19:103–111, 2004. © 2004 Wiley‐Liss, Inc.
Incorporating pathologists' criteria of malignancy into the evolutionary model for cancer development
Authors: Fischer Andrew H. , Young Kyle A. , DeLellis Ronald A.
Published: July 2004

A wide variety of alterations in cell and tissue structure still form the basis for cancer diagnosis by pathologists. Cancer development is recognized to be an evolutionary process [Foulds, 1954; Cairns, 1975; Nowell, 1976; Sager, 1982; Tomlinson et al., 1996; Cahill et al., 1999; Tomlinson and Bodmer, 1999], but the phenotypic changes diagnostic of cancer (pathologists' “criteria of malignancy”) have not been integrated into the existing evolutionary framework. Since phenotypic changes bear an important relationship to the genetic and physiologic changes underlying Darwinian evolution, we propose that diagnostic structural alterations also bear an important and predictable relation to both the cancer genes and the functional alterations active at any particular step in the development of a cancer. Cancer genes are predicted to mediate the acquisition of cellular‐level diagnostic criteria and the diagnostic cellular‐level structural changes should reflect in a useful manner the altered cell physiology required for the cell to achieve increased “cellular fitness” at any particular step of colonal evolution. Tissue‐level criteria of malignancy should relate less directly to specific cancer genes, but tissue‐level criteria should still provide essential insight into the interplay of the altered cellular fitness with the constraints imposed by the cells' microenvironment. The evolutionary framework allows tissue‐level criteria of malignancy to be expressed in terms of viable hypotheses for the mechanism of clonal expansion at any particular step in cancer development. This approach to conveying the tissue‐level criteria of malignancy complements pattern recognition approaches to diagnosis, and establishes common ground between pathology and cell biology. When viewed from this perspective, the functions of cancer genes appear quite different from those predicted by the “Gatekeeper, Caretaker” or “Hallmarks of Cancer” models. Finally, a full evolutionary framework incorporating the criteria of malignancy restores congruity between the histogenetic classification and the emerging molecular classification of cancer. © 2004 Wiley‐Liss, Inc.
Histone modification in constitutive heterochromatin versus unexpressed euchromatin in human cells
Authors: Jiang Guanchao , Yang Fan , Sanchez Cecilia , Ehrlich Melanie
Published: July 2004

Histone modifications are implicated in regulating chromatin condensation but it is unclear how they differ between constitutive heterochromatin and unexpressed euchromatin. Chromatin immunoprecipitation (ChIP) assays were done on various human cell populations using antibodies specific for acetylated or methylated forms of histone H3 or H4. Analysis of the immunoprecipitates was by quantitative real‐time PCR or semi‐quantitative PCR (SQ‐PCR). Of eight tested antibodies, the one for histone H4 acetylated at lysine 4, 8, 12, or 16 was best for distinguishing constitutive heterochromatin from unexpressed euchromatin, but differences in the extent of immunoprecipitation of these two types of chromatin were only modest, although highly reproducible. With this antibody, there was an average of 2.5‐fold less immunoprecipitation of three constitutive heterochromatin regions than of four unexpressed euchromatic gene regions and about 15‐fold less immunoprecipitation of these heterochromatin standards than of two constitutively expressed gene standards (P < 0.001). We also analyzed histone acetylation and methylation by immunocytochemistry with antibodies to H4 acetylated at lysine 8, H3 trimethylated at lysine 9, and H3 methylated at lysine 4. In addition, immunocytochemical analysis was done with an antibody to heterochromatin protein 1α (HP1α), whose preferential binding to heterochromatin has been linked to trimethylation of H3 at lysine 9. Our combined ChIP and immunocytochemical results suggest that factors other than hypoacetylation of the N‐terminal tails of H4 and hypermethylation of H3 at lysine 9 can play an important role in determining whether a chromatin sequence in mammalian cells is constitutively heterochromatic. © 2004 Wiley‐Liss, Inc.
Candidate cis‐elements for human renin gene expression in the promoter region
Authors: Konoshita Tadashi , Makino Yasukazu , Wakahara Shigeyuki , Ido Kanako , Yoshida Masahiro , Kawai Yasuyuki , Miyamori Isamu
Published: July 2004

The regulation of renin gene expression, the rate‐limiting enzyme of the system, is thought to be fundamental to the total system. Previously, we mapped six putative cis‐elements in the promoter region of the human renin gene with nuclear proteins from human chorionic cells and human renal cortex by DNase I protection assay (footprint A–F). Each footprint contains Ets motif like site (A), HOXñPBX recognition sequence (B), unknown sequence as DNA binding consensus (C), CRE (D), COUP‐TFII (ARP‐1) motif like site (E), and AGE3 like site (F). Footprint D has been characterized by means of functional studies as the genuine human renin gene CRE interacting with CREB in cooperation with the site of footprint B. To obtain further clues to the specific expression in the promoter region, these putative cis‐elements were conducted to a consensus‐specific binding assay to compare renin‐producing and non‐renin‐producing cells by EMSA and electromobility super‐shift assay. Different sequence‐specific DNA/protein binding was obtained among the different cell lines with footprint B site, with COUP‐TFII (ARP‐1) motif like site and possibly with footprint F site. The results implicate these putative cis‐elements and each corresponding trans‐factor in the specific expression of the human renin gene in the promoter region. Further functional characterization of these elements would provide important data for a better understanding of human renin gene expression. © 2004 Wiley‐Liss, Inc.
Inhibitory helix‐loop‐helix transcription factors Id1/Id3 promote bone formation in vivo
Authors: Maeda Yukiko , Tsuji Kunikazu , Nifuji Akira , Noda Masaki
Published: July 2004

Bone formation is under the control of a set of transcription factors. Ids are inhibitory helix‐loop‐helix (HLH) transcription factors and expression of Id genes in osteoblasts is under the control of calciotropic agents such as BMP and vitamin D. However, the function of Ids during bone formation in vivo has not yet been elucidated. We, therefore, examined the role of Id1 and Id3 in the regulation of bone metabolism in vivo. Using wild type and Id1/Id3 heterozygous knockout mice, we analyzed calvarial bone formation in the suture by X‐ray picture, proliferation, and mineralization activities of primary calvarial osteoblasts by MTT assay and alizarin red staining and onthotopic in vivo bone formation by BMP injection onto calvaria and micro CT analysis. The width of calvarial sutures was reduced by more than 50% in Id1/Id3 heterozygous knock out mice. Analyses on the cellular basis for the mechanism underlying the defects in the mutant mice revealed suppression of proliferation and mineralization in osteoblasts derived from Id1/Id3 heterozygous knock out mice. Furthermore, Id1/Id3 heterozygous knock out mice suppressed BMP‐induced bone formation in vivo. These results indicated that Id1 and Id3 are positive factors to promote bone formation in vivo. © 2004 Wiley‐Liss, Inc.
Zinc stabilizes adenomatous polyposis coli (APC) protein levels and induces cell cycle arrest in colon cancer cells
Authors: Jaiswal Aruna S. , Narayan Satya
Published: July 2004

In the present study, we investigated the mechanisms by which zinc causes growth arrest in colon cancer cells. The results suggest that zinc treatment stabilizes the levels of the wild‐type adenomatous polyposis coli (APC) protein at the post‐translational level since the APC mRNA levels and the promoter activity of the APC gene were decreased in HCT‐116 cells (which express the wild‐type APC gene) after treatment with ZnCl2. Increased levels of wild‐type but not truncated APC proteins were required for the ZnCl2‐mediated G2/M phase arrest in different colon cancer cell lines. We further tested whether serum‐stimulation, which induces cell cycle arrest in the S phase, can relieve ZnCl2‐induced G2/M phase arrest of HCT‐116 cells. Results showed that in the HCT‐116 cells pretreated with ZnCl2, the serum‐stimulation neither changed the distribution of G2/M phase arrested cells nor the increased levels of APC protein. The G2/M phase arrest correlated with retarded growth of HCT‐116 cells. To further establish that wild‐type APC protein plays a role in ZnCl2‐induced G2/M arrest, we treated SW480 colon cancer cells that express truncated APC protein. We found that ZnCl2 treatment did not induce G2/M phase arrest in SW480 cells; however, the cell growth was retarded due to the loss of E‐cadherin and α‐tubulin levels. These results suggest that ZnCl2 inhibits the proliferation of colon cancer cells (which carry the wild‐type APC gene) through stabilization of the APC protein and cell cycle arrest in the G2/M phase. On the other hand, ZnCl2 inhibits the proliferation of colon cancer cells (which carry the mutant APC gene) by disrupting cellular attachment and microtubule stability. © 2004 Wiley‐Liss, Inc.
PTH and phospholipase A2 in the aging process of intestinal cells
Authors: Gentili Claudia , Morelli Susana , de Boland Ana Russo
Published: July 2004

In this study we analyzed, for the first time, alterations in phospholipase A2 (PLA2) activity and response to parathyroid hormone (PTH) in rat enterocytes with aging. We found that PTH, rapidly stimulate arachidonic acid (AA) release in rat duodenal cells (+1‐ to 2‐fold), an effect that is greatly potentiated by aging (+4‐fold). We also found that hormone‐induced AA release in young animals is Ca2+‐dependent via cPLA2, while AA released by PTH in cells from aged rats is due to the activation of cPLA2 and the Ca2+‐independent PLA2 (iPLA2). In enterocytes from 3 months old rats, PTH induced, in a time and dose‐dependent fashion, the phosphorylation of cPLA2 on serine 505, with a maximun at 10 min (+7‐fold). Basal levels of cPLA2 serine‐phosphorylation were higher in old enterocytes, affecting the hormone response which was greatly diminished (+2‐fold at 10 min). cPLA2 phosphorylation impairment in old animals was not related to changes of cPLA2 protein expression and did not explain the substantial increase on PTH‐induced AA release with aging, further suggesting the involvement of a different PLA2 isoform. Intracellular Ca2+ chelation (BAPTA‐AM, 5 μM) suppressed the serine phosphorylation of cPLA2 in both, young and aged rats, demonstrating that intracellular Ca2+ is required for full activation of cPLA2 in enterocytes stimulated with PTH. Hormone effect on cPLA2 was suppressed to a great extent by the MAP kinases ERK 1 and ERK2 inhibitor, PD 98059 (20 μM), the cAMP antagonist, Rp‐cAMP, and the PKC inhibitor Ro31820 both, in young and aged animals. Enterocytes exposure to PTH also resulted in phospho‐cPLA2 translocation from cytosol to nuclei and membrane fractions, where phospholipase subtrates reside. Hormone‐induced enzyme translocation is also modified by aging where, in contrast to young animals, part of phospho‐cPLA2 remained cytosolic. Collectively, these data suggest that PTH activates in duodenal cells, a Ca2+‐dependent cytosolic PLA2 and attendant AA release and that this activation requires prior stimulation of intracellular ERK1/2, PKA, and PKC. cPLA2 is the major enzyme responsible for AA release in young enterocytes while cPLA2 and the Ca2+‐independent iPLA2, potentiate PTH‐induced AA release in aged cells. Impairment of PTH activation of PLA2 isoforms upon aging may result in abnormal hormone regulation of membrane fluidity and permeability and thereby affecting intestinal cell membrane function.
PI‐3‐kinase/NF‐κB mediated response of Jurkat T leukemic cells to two different chemotherapeutic drugs, etoposide and TRAIL
Authors: Sabatini N. , Di Pietro R. , Rapino M. , Sancilio S. , Comani S. , Cataldi A.
Published: July 2004

Jurkat T leukemic cells respond to Etoposide, antineoplastic agent which targets the DNA unwinding enzyme, Topoisomerase II, and TNF‐Related‐Apoptosis‐Inducing‐Ligand (TRAIL), 34 kDa transmembrane protein, which displays minimal or no toxicity on normal cells and tissues, not only disclosing the occurrence of apoptosis but also a kind of resistance. A similar rate of viability upon the exposure to these two drugs up to 24 h has been evidenced, followed by the occurrence of a rescue process against TRAIL, not performed against Etoposide, along with an higher number of dead cells upon Etoposide exposure, in comparison with TRAIL treatment. These preliminary results let us to speculate on the possible involvement of PI‐3‐kinase in TRAIL resistance disclosed by surviving cells (20%), may be phosphorylating Akt‐1 and, in parallel, IκB α on both serine and tyrosine residues. On the other hand, in Etoposide Jurkat exposed cells Ser 32‐36 phosphorylation of IκB α is not sufficient to overbalance the apoptotic fate of the cells, since Bax increase, IAP decrease, and caspase‐3 activation determine the persistence of the apoptotic state along with the occurrence of cell death by necrosis. Thus, the existence of a balance between apoptotic and rescue response in 20% of cells surviving to TRAIL suggests the possibility of pushing it in favor of cell death in order to improve the yield of pharmacological strategies. © 2004 Wiley‐Liss, Inc.
Human cytomegalovirus pp71: A new viral tool to probe the mechanisms of cell cycle progression and oncogenesis controlled by the retinoblastoma family of tumor suppressors
Authors: Kalejta Robert F.
Published: July 2004

The DNA tumor virus oncogenes (adenovirus E1A, simian virus 40 (SV40) large T antigen, and papillomavirus E7) have been instrumental in illuminating the molecules and mechanisms of cell cycle progression and carcinogenesis. However, since these multifunctional proteins target so many important cellular regulators, it is sometimes difficult to establish the functional importance of any individual interaction. Perhaps a herpesvirus protein, newly defined as a cell cycle regulator, can help address these issues. Like the DNA tumor virus proteins, the human cytomegalovirus (HCMV) pp71 protein contains a retinoblastoma protein (Rb) binding motif (LxCxD), and stimulates DNA synthesis in quiescent cells. Unlike E1A, T antigen, and E7, pp71 expression does not induce apoptosis, nor does it cooperate to transform primary cells. Determining how pp71 induces cell cycle progression without invoking apoptosis or leading to cellular transformation may help in defining the signals that ultimately lead to these processes. © 2004 Wiley‐Liss, Inc.
Binding of MCF‐7 cell mitochondrial proteins and recombinant human estrogen receptors α and β to human mitochondrial dna estrogen response elements
Authors: Chen Jin Q. , Eshete Matthewos , Alworth William L. , Yager James D.
Published: July 2004

Our previous studies have shown that 17β estradiol (E2) enhances the transcript levels of mitochondrial DNA (mtDNA)‐encoded genes and mitochondrial respiratory chain (MRC) activity via estrogen receptors (ER). Others have reported the presence of putative estrogen responsive elements (ERE) in human mtDNA (mtEREs) and detection of ERs in mitochondria of rat uterine and ovary cells. Recently, we demonstrated the E2‐enhanced mitochondrial localization of ERα and ERβ, and E2‐induced mtDNA transcript levels in MCF‐7 cells. In this study, we applied electrophoresis mobility shift assays (EMSAs) and surface plasmon resonance (SPR) to determine if mitochondrial extracts, recombinant human ERα (rhERα), and rhERβ interact with mtEREs. Using EMSAs, we observed that ER‐containing mitochondrial extracts bound to mtEREs and the binding was enhanced by E2, whereas the binding of mitochondrial proteins from ERβ‐deficient cells was almost undetectable. Both rhERα and rhERβ bound to the mtEREs and their binding was altered by their respective antibodies. However, the ERα antibodies did not alter the binding of MCF‐7 cell mitochondrial extracts to mtEREs whereas the binding MCF‐7 and MDA‐MB‐231 cell mitochondrial extracts to mtEREs was reduced by ERβ antibody. These results suggest that the mtERE‐bound mitochondrial protein is ERβ. Using SPR, we observed the binding of both ERs to mtEREs and that the binding was increased by E2. These results indicate that the mitochondrial ERs can interact with mtEREs and suggest that they may be directly involved in E2 induction of mtDNA transcription. © 2004 Wiley‐Liss, Inc.
Regulation of cell signalling cascades by steroid hormones
Authors: Cheskis Boris J.
Published: July 2004

Steroid hormones control a wide variety of cellular functions important for cell homeostasis, proliferation, differentiation, and apoptosis. Evidence collected in the last few years indicates that this regulation is mediated by a complex interface of direct control of gene expression (so‐called “transcriptional” action, driven by receptors that are localized in cell nucleus) and by regulation of cell signaling/phosphorylation cascades (“extranuclear” action, mediated by receptors that are localized in close proximity to cellular membrane). Regulation of gene expression takes place via ligand‐dependent receptor binding to target gene promoters as part of the preinitiation complex, which leads to chromatin remodeling and ultimately regulates the rate of gene expression. Steroid‐mediated regulation of cell signaling does not depend on gene transcription or protein biosynthesis. The molecular mechanism of this phenomenon is not fully understood. This review will focus on recent developments related to our understanding of the molecular mechanism of the extranuclear action of steroid hormones. © 2004 Wiley‐Liss, Inc.
Dexamethasone inhibits insulin‐induced chondrogenesis of ATDC5 cells by preventing PI3K‐Akt signaling and DNA binding of Runx2
Authors: Fujita Takashi , Fukuyama Ryo , Enomoto Hirayuki , Komori Toshihisa
Published: July 2004

Glucocorticoids play important roles in cell growth and differentiation. In this study, we investigated the effect of application of dexamethasone (DEX) at the early stage of chondrogenesis using the prechondrogenic cell line, ATDC5, which differentiates into chondrocytes in the presence of insulin. When ATDC5 cells were cultured in the presence of DEX and insulin, DEX inhibited insulin‐induced cellular condensation and subsequent cartilaginous nodule formation, and reduced proteoglycan synthesis and type II collagen expression dose‐dependently. Pretreatment with 10−8 M DEX for 1 day inhibited insulin‐induced Akt phosphorylation, but not ERK1/2 phosphorylation, in ATDC5 cells. Treatment of ATDC5 cells with insulin for more than 2 days upregulated the levels of phosphatidylinositol 3‐kinase (PI3K) subunit proteins, p85 and p110, and Akt, whereas the upregulation was inhibited in the presence of 10−8 M DEX. In electrophoresis mobility shift assays (EMSAs), treatment with 10−8 M DEX inhibited DNA binding of Runx2 during culture of ATDC5 cells with insulin. Reporter assays using osteocalcin promoter showed that DEX inhibited Runx2‐dependent transcription dose‐dependently. Adenoviral introduction of dominant‐negative (dn)‐Akt or dn‐Runx2 into ATDC5 cells inhibited cellular condensation and reduced proteoglycan synthesis upon incubation with insulin, whereas adenoviral introduction of Akt or Runx2 prevented the inhibition of chondrogenesis by DEX. These findings indicate that DEX inhibits chondrogenesis of ATDC5 cells at the early stage by downregulating Akt phosphorylation as well as the protein levels of PI3K subunits and Akt, thereby suppressing PI3K‐Akt signaling, and by inhibiting DNA binding of Runx2 and Runx2‐dependent transcription. © 2004 Wiley‐Liss, Inc.
Mechanisms regulating the origins of the vertebrate vascular system
Authors: Saha Margaret S. , Cox Elizabeth A. , Sipe Conor W.
Published: July 2004

In order to sustain growth, differentiation, and organogenesis, vertebrate embryos must form a functional vascular system early in embryonic development. Intrinsic interest in this process as well as the promise of potential clinical applications has led to significant progress in understanding the mechanisms governing the formation of the vascular system, however the earliest stages of vascular development—the emergence of committed endothelial precursors from the mesoderm—remain unclear. A review of the current literature reveals an unexpected diversity and heterogeneity with respect to where vascular endothelial cells originate in the embryo, when they become committed and the mechanisms governing how endothelial cells acquire their identity. Spatially, a widespread region of the early mesoderm possesses the ability to give rise to vascular endothelial cells; temporally the process is not limited to a small window during embryogenesis, but rather, may continue throughout the lifespan of the organism. On the molecular level, recent findings point to several determinative pathways that regulate, modulate, and extend the scope of the Flk1/VEGF signaling system. An expanding array of novel gene products implicated in endothelial cell type determination appear to act synergistically, with different combinations of factors leading to diverse cellular responses, varying patterns of differentiation, and considerable heterogeneity of endothelial cell types during embryogenesis. © 2004 Wiley‐Liss, Inc.