bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of MIMO systems with respect to front‐end imperfections
Authors: Degen Christoph , Koch Olivier , Keusgen Wilhelm , Rembold Bernhard
Published: May 2006

In multiuser multiple‐input multiple‐output (MIMO) systems the performance of joint detection and joint predistortion techniques highly depends on the quality of radio‐frequency (RF) components. Therefore, the focus of this paper is on front‐end imperfections. We demonstrate the influence of erroneous calibration (which is essential for downlink predistortion), phase noise and nonlinear amplifiers. For all issues we elaborate on the different disturbances that arise, analyse the impact on symbol estimation and evaluate system performance in terms of coded bit error ratio (BER). A general result for all examined front‐end imperfections is that their influence increases with the number of spatially multiplexed data streams culminating in unacceptable performance degradation in fully loaded systems. Moreover, Wiener‐based detection and predistortion reduces the degradation due to front‐end imperfections in low SNR regimes compared to zero forcing. Copyright © 2006 AEIT
On time‐varying cyclic delay diversity
Authors: Richter Gerd , Bossert Martin , Costa Elena , Weckerle Martin
Published: May 2006

Cyclic delay diversity (CDD) was introduced in 2001 to obtain spatial diversity in an orthogonal frequency division multiplexing (OFDM) based transmission system. In contrast to space‐time codes, CDD introduces no additional effort at the receiver side, since CDD changes only the channel impulse response seen by the receiver by increasing the frequency selectivity. Furthermore, CDD has the advantage that there is no rate loss even for more than two transmit antennas. In this paper, we analyse CDD for an orthogonal frequency division multiple access (OFDMA) based transmission system. To increase not only the frequency selectivity but also the time selectivity, we introduce time‐varying cyclic delay diversity (TV‐CDD), which changes the cyclic shift with each OFDM symbol. Especially in systems, where each user can only allocate a few subcarriers for data transmission, TV‐CDD improves the performance of the OFDMA‐based transmission system significantly. Copyright © 2006 AEIT
The turbo‐fountain
Authors: Jenkač Hrvoje , Hagenauer Joachim , Mayer Timo
Published: May 2006

Reliable wireless broadcast with asynchronous data access based on fountain coding is investigated. We review the traditional problem formalisation for fountain codes operating on erasure channels, and we generalise the problem formalisation to more general channels. We introduce a novel type of rateless codes based on the Turbo Principle: theTurbo‐Fountain. The Turbo‐Fountain is able to consider soft information from the channel in the decoding process. Two realisations for the Turbo‐Fountain are introduced. We show simulation results for the Turbo‐Fountain realisations on the AWGN and on fading channels. Additionally, we compare the achievable Turbo‐Fountain performance with traditional fountain codes designed for the erasure channel, both on the AWGN and on fading channels, considering an appropriate erasure declaration. It is shown that the Turbo‐Fountain provides significant performance gains, due to exploitation of soft information, and approaches capacity. Moreover, we investigate the Turbo‐Fountain within the framework ofjoint source‐fountain coding. We show that the Turbo‐Fountain provides the additional ability of lossless source compression and outperforms a system with separate source coding followed by fountain coding. Copyright © 2006 AEIT
MMSE turbo equalisation for real‐valued symbols
Authors: Dietl Guido , Utschick Wolfgang
Published: May 2006

This paper deals withiterativeorturbo receiverswhere themaximum a posteriori detectorhas been replaced by awidely linear filterminimising themean square error, that is the widely linearWiener Filter(WF). In communication systems where the transmitted symbols can be assumed to be realisations of a non‐circular random variable, widely linear processing outperforms the linear one. Besides the non‐circularity due to thea prioriinformation fed back in the turbo scheme, we investigate real‐valued modulation alphabets which are non‐circular even if thea prioriinformation is zero. We derive the widely linear WF for this case and observe that the number offloating point operationsinvolved in its computation, is higher than the one of the linear WF. Nevertheless, they have the same order of computational complexity. Moreover, we reveal the relationship between the proposed widely linear equaliser andinterference cancellationbased on the availablea prioriinformation. Simulation results of a frequency‐selective turbo system show that despite of the increased computational complexity, the performance gain of widely linear processing compared to the linear one, is negligible. However, in systems without turbo feedback, the widely linear WF outperforms tremendously the linear one. Copyright © 2006 AEIT
Radio propagation in frequency selective buildings
Authors: Raspopoulos Marios , Chaudhry Farhan A. , Stavrou Stavros
Published: May 2006

This work proposes the deployment of frequency selective surfaces (FSS) in indoor wireless environments and investigates their effect on radio wave propagation. FSS could be used to isolate coverage in indoor areas by increasing the transmission loss through the interfaces. At the same time they can channel the signals into other areas of interest. Simulations have been carried out at two frequencies in order to verify the frequency selectivity of FSS. Copyright © 2006 AEIT
Comparison of modified dual queue and EDCA for VoIP over IEEE 802.11 WLAN
Authors: Yu Jeonggyun , Choi Sunghyun
Published: May 2006

The popular IEEE 802.11 WLAN today does not provide any quality of service (QoS) because of its contention‐based channel access nature of the medium access control (MAC). A simple software upgrade‐based solution, called a dual queue scheme, can be used to provide QoS to real‐time services such as Voice‐over‐IP (VoIP). The dual queue scheme operates on top of the legacy MAC. In this paper, we present a modified dual queue (MDQ) scheme by considering a practical implementation limitation. On the other hand, the emerging 802.11e MAC includes a contention‐based channel access mechanism, called enhanced distributed channel access (EDCA). Prioritized channel accesses are provided to different traffic classes under EDCA.

In this paper, we comparatively evaluate the performances of MDQ and EDCA via simulations in terms of delay, jitter and throughput for various scenarios. We also compare the two access schemes when multiple transmission rates are used via rate adaptation mechanism for reliable transmission over erroneous wireless channel. The simulation results show that EDCA apparently provides a better performance in most situations. However, MDQ provides an acceptable performance close to that of EDCA so that it can be used when the EDCA is not available and/or the hardware upgrade to 802.11e is not desirable for the cost reason. Copyright © 2006 AEIT
Response to intraarterial induction chemotherapy: A prognostic parameter in oral and oropharyngeal cancer
Authors: Kovács Adorján F.
Published: May 2006

Background.

Patients with head and neck cancer and good pathologic response to neoadjuvant systemic induction chemotherapy have a better prognosis for survival than do those with stable or progressive disease. Thus, induction chemotherapy could theoretically help in stratifying further treatment, but toxicity is much too high. The prognostic implication of superselective intraarterial high‐dose cisplatin administered by a femoral approach, which has much less toxicity, is not yet known.

Methods.

One hundred eighty‐seven unselected consecutive patients with previously untreated oral and oropharyngeal squamous cell carcinoma received intraarterial high‐dose cisplatin for induction and were assessed for response by visual examination and palpation. This treatment was followed by surgery and adjuvant radiation with concomitant systemic chemotherapy. Omission of a modality depended on individual contraindications and not on preselection. The consequence of omissions has been the constitution of several treatment arms. The overall and disease‐free survival in relation to clinical local response after intraarterial induction chemotherapy was calculated using the Kaplan–Meier method. Additional analysis excluded bias caused by stages and treatment arms.

Results.

Explorative statistics using the log‐rank and chi‐square tests demonstrated a strong prognostic relevance of response to intraarterial chemotherapy irrespective of stage and treatment.

Conclusions.

Our results are encouraging for prospective randomized studies and molecular genetic investigations with intraarterial chemotherapy. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
Microsatellite instability as an indicator of malignant progression in laryngeal premalignancy
Authors: Sardi Iacopo , Franchi Alessandro , De Campora Luca , Passali Giulio Cesare , Gallo Oreste
Published: May 2006

Background.

Microsatellite instability (MSI) is considered a novel marker of genetic instability, and preliminary studies have shown that it may provide useful information in assessing the risk of malignant progression in preinvasive lesions.

Methods.

We analyzed MSI in serial biopsy specimens from 10 patients with preinvasive laryngeal lesions and corresponding metachronous laryngeal cancers compared with biopsy specimens of similar lesions without malignant transformation from 20 subjects in a match‐paired analysis. MSI was determined by assessing the status of 14 microsatellite markers (chromosome loci: 2p16, 3q21‐24, 4q12, 9p21, 13q14, 16q22.1, 17p12 and 21q21) in DNA biopsy specimens.

Results.

MSI+ (aberration at two or more loci) was detected in seven of 10 patients with premalignant lesions progressed to carcinoma, whereas only four of the 20 biopsy specimens from control subjects showed an unstable phenotype (p < .01). Interestingly, preinvasive laryngeal lesions with MSI at hMSH2/hMSH6 loci frequently had instability at one or more additional loci and were considered as MSI+ (overall in eight of 12 cases: six premalignant lesions progressed to cancer and one without progression of the original laryngeal lesion, p < .01). The immunohistochemical analysis of the hMSH2 protein expression in our series, however, did not suggest its involvement in laryngeal carcinogenesis.

Conclusions.

Our study indicates that MSI is more common in preneoplastic laryngeal lesions progressing to cancer, thus suggesting that microsatellite status assessment may be useful in determining the risk of malignant progression in patients with preinvasive laryngeal lesions for whom chemopreventive and multiple endoscopic protocols can be attempted. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
Genetic polymorphisms of CYP1A1, CYP2E1, GSTM1, and GSTT1 associated with head and neck cancer
Authors: Gattás Gilka Jorge Figaro , de Carvalho Marcos Brasilino , Siraque Maria Salete , Curioni Otávio A. , Kohler Priscila , Eluf‐Neto Jose , Wünsch‐Filho Victor
Published: May 2006

Background.

Alcohol intake and tobacco smoke, in addition to other environmental and genetic factors, have been associated with head and neck cancer. We evaluated the role of metabolic enzyme polymorphisms on the risk of head and neck cancer in a hospital‐based case‐control study.

Methods.

CYP1A1MspI, CYP2E1PstI, GSTM1, and GSTT1polymorphisms were evaluated in 103 histologically confirmed head and neck cancer cases and 102 controls by means of polymerase chain reaction–restriction fragment length polymorphism methods.

Results.

GSTM1null increased the risk of head and neck cancer (odds ratio [OR], 2.2; 95% confidence interval [95% CI], 1.24–3.79), oral cancer (OR, 2.8; 95% CI, 1.28–5.98), and pharyngeal cancer (OR, 2.2; 95% CI, 1.08–4.63). CYP2E1PstI polymorphism indicated a risk for oral cancer (OR, 3.6; 95% CI, 1.29–11.56). The joint effect of GSTM1 null and CYP1A1 polymorphism increased the risk of head and neck cancer (OR, 2.4; 95% CI, 1.13–5.10).

Conclusions.

GSTM1 null alone or associated with CYP1A1 increased the risk of head and neck cancer; the CYP2E1PstI mutated allele increased the risk for only oral cancer. © 2006 Wiley Periodicals, Inc. Head Neck, 2006.
Kaposiform hemangioendothelioma arising in the ethmoid sinus of an 8‐year‐old girl with severe epistaxis
Authors: Birchler Manfred T. , Schmid Stephan , Holzmann David , Stallmach Thomas , Gysin Claudine
Published: May 2006

Background.

Epistaxis is very common during childhood. It occurs primarily in boys and is usually self‐limiting. Trauma and nose picking are among the most common causes. In general, epistaxis can be easily treated with anterior nasal packing or electrocoagulation.

Methods.

We report a case of an 8‐year‐old girl with severe unilateral epistaxis.

Results.

The bleeding originated from a kaposiform hemangioendothelioma arising in the left nasal cavity and ethmoid sinus. The feeding vessels originating from the maxillary artery were first embolized. The tumor was then surgically removed through a combined external ethmoidectomy and endonasal approach. The postoperative course was uneventful. MRI at 6 months after surgery showed no tumor recurrence.

Conclusions.

We report a previously undescribed cause of epistaxis in children, namely, a kaposiform hemangioendothelioma. To our knowledge, this is the first such case in the English‐language literature. The differential diagnosis of severe unilateral nasal bleeding among the pediatric population should include the possibility of a kaposiform hemangioendothelioma. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
First clinical case of boron neutron capture therapy for head and neck malignancies using 18F‐BPA PET
Authors: Aihara Teruhito , Hiratsuka Junichi , Morita Norimasa , Uno Masako , Sakurai Yoshinori , Maruhashi Akira , Ono Koji , Harada Tamotsu
Published: May 2006

Background.

We investigated the application of boron neutron capture therapy (BNCT) to suitable cancers other than glioblastoma and melanoma. Head and neck malignancies were consequently selected as adaptable cancers. We reported the clinical results of our first case treated and discussed several advantages to the application of BNCT to head and neck tumors.

Methods.

The patient was a 48‐year‐old woman with recurrent submandibular gland cancer. We confirmed the p‐boronophenylalanine (BPA)‐accumulating capacity of the tumor by fluorine‐18‐labeled p‐boronophenylalanine positron emission tomography (18F‐BPA PET) before BNCT. The tumor/normal tissue boron concentration ratio was 2.9. The patient underwent a preirradiation CT scan for treatment planning performed using the “SERA” software program. The tumor was irradiated at the Kyoto University Research Reactor with epithermal neutrons 5 MW for 90 minutes. The tumor dose and normal tissue dose calculated ranged from 20.0 to 25.2 Gy and from 3.2 to 5.8 Gy, respectively.

Results.

To date there has been continuous complete regression in the tumor and no acute and chronic complications for 1.5 years.

Conclusions.

Although only 1 patient has shown complete regression and additional long‐term follow‐up should be required to assess this treatment, we believe that head and neck tumors are suitable for BNCT and that such excellent results will have a great impact on patients in the near future. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
Primary and salvage (hypo)pharyngectomy: Analysis and outcome
Authors: Clark Jonathan R. , de Almeida John , Gilbert Ralph , Irish Jonathan , Brown Dale , Neligan Peter , Gullane Patrick J.
Published: May 2006

Background.

Surgery for squamous cell carcinoma (SCC) arising or extending to the hypopharynx is generally reserved for advanced disease or salvage. The prognosis of patients requiring pharyngectomy is poor, and the perioperative morbidity is significant. The aim of the present study is to describe the disease‐related and treatment‐related outcomes of patients undergoing primary and salvage pharyngectomy for cancer of the hypopharynx and larynx over a 10‐year period from a single institution.

Methods.

We retrospectively reviewed 138 partial and circumferential pharyngectomies performed at a tertiary referral center between 1992 and 2002. There were 31 females and 107 males. The median age was 62 years (range, 27–81 years), and mean follow‐up was 3.6 years. Salvage pharyngectomy for radiation failure was performed in 72 patients (52%), and in 66 patients (48%) pharyngectomy was performed as the primary treatment.

Results.

The 5‐year overall survival rate after salvage pharyngectomy was 31% and after primary pharyngectomy was 38%. The 5‐year disease‐specific survival (DSS) for salvage was 40% and after primary surgery was 45%. The 5‐year local and regional control rates for salvage pharyngectomy were 71% and 70%, respectively, and for primary pharyngectomy were 79% and 67%, respectively. The perioperative mortality rate was 3.6%, and the combined morbidity rate was 70%. Postoperative hypocalcemia developed in 44% of patients, a pharyngocutaneous fistula developed in 31% of patients, and the long‐term stricture rate was 15%. Variables adversely affecting DSS on univariate analysis were nodal metastases (p = .044), extracapsular spread (ECS) (p = .006), poorly differentiated tumors (p = .015), lymphovascular invasion (p = .042), and positive tumor margins (p = .026). ECS (p = .023) was the only independent prognostic variable on multivariable analysis; however, there was a trend toward significance for nodal metastases (p = .064) and tumor differentiation (p = .079).

Conclusion.

This study demonstrates that both salvage pharyngectomy and primary surgery for advanced disease are viable options with high locoregional control. However, this represents a high‐risk group in terms of both operative morbidity and survival. Patients with nodal metastases, ECS, and poorly differentiated tumors are likely to succumb to their disease and should be selected for adjuvant therapy when possible. © 2006 Wiley Periodicals, Inc. Head Neck 28: 671–677, 2006
Expression of xenobiotic and steroid hormone metabolizing enzymes in human breast carcinomas
Authors: Haas Susanne , Pierl Christiane , Harth Volker , Pesch Beate , Rabstein Sylvia , Brüning Thomas , Ko Yon , Hamann Ute , Justenhoven Christina , Brauch Hiltrud , Fischer Hans‐Peter
Published: May 2006

The potential to metabolize endogenous and exogenous substances may influence breast cancer development and tumor growth. Therefore, the authors investigated the protein expression of Glutathione S‐transferase (GST) isoforms and cytochrome P450 (CYP) known to be involved in the metabolism of steroid hormones and endogenous as well as exogenous carcinogens in breast cancer tissue to obtain new information on their possible role in tumor progression. Expression of GST pi, mu, alpha and CYP1A1/2, 1A2, 3A4/5, 1B1, 2E1 was assessed by immunohistochemistry for primary breast carcinomas of 393 patients from the German GENICA breast cancer collection. The percentages of positive tumors were 50.1 and 44.5% for GST mu and CYP2E1, and ranged from 13 to 24.7% for CYP1A2, GST pi, CYP1A1/2, CYP3A4/5, CYP1B1. GST alpha was expressed in 1.8% of tumors. The authors observed the following associations between strong protein expression and histopathological characteristics: GST expression was associated with a better tumor differentiation (GST mu, p = 0.018) and with reduced lymph node metastasis (GST pi, p = 0.02). In addition, GST mu expression was associated with a positive estrogen receptor and progesterone receptor status (p < 0.001). CYP3A4/5 expression was associated with a positive nodal status (p = 0.018). Expression of CYP1B1 was associated with poor tumor differentiation (p = 0.049). Our results demonstrate that the majority of breast carcinomas expressed xenobiotic and drug metabolizing enzymes. They particularly suggest that GST mu and pi expression may indicate a better prognosis and that strong CYP3A4/5 and CYP1B1 expression may be key features of nonfavourable prognosis. © 2006 Wiley‐Liss, Inc.
Resistance to apoptosis of HCW‐2 cells can be overcome by curcumin‐ or vincristine‐induced mitotic catastrophe
Authors: Magalska Adriana , Sliwinska Malgorzata , Szczepanowska Joanna , Salvioli Stefano , Franceschi Claudio , Sikora Ewa
Published: May 2006

The term mitotic catastrophe has recently become widely used to describe a form of death affecting many cancer cells, which, because of severe DNA or mitotic spindle damage, are not able to bypass mitosis. We show here that cells of the HL‐60‐derived HCW‐2 line highly resistant to apoptosis, upon treatment with curcumin or vincristine, undergo mitotic catastrophe that is finalized by caspase 3 activation and oligonucleosomal DNA degradation. Curcumin is a natural dye, derived from Curcuma longa that has been shown to induce cell death in many cancer cells. Both treatments decrease cell proliferation and cell survival, arrest cells in G2/M phase of cell cycle and induce morphological changes characterized by cell enlargement and micronucleation. “Catastrophic” cells comprise a separate subpopulation with less than 4C DNA, as evidenced by flow and scanning cytometry. This subpopulation is MPM‐2 positive. Thymidine block increased the number of cell arrested in the G2/M phase of cell cycle and curcumin effectiveness as an inducer of mitotic catastrophe. Curcumin, but not vincristine, acts on HCW‐2 cells by inhibiting the expression of survivin, a modulator of cell division and apoptosis in cancer. Altogether our results show that apoptosis resistance can be overcome by inducing mitotic catastrophe in HCW‐2 cells. © 2006 Wiley‐Liss, Inc.
p53 Arg72Pro polymorphism and risk of colorectal adenoma and cancer
Authors: Koushik Anita , Tranah Gregory J. , Ma Jing , Stampfer Meir J. , Sesso Howard D. , Fuchs Charles S. , Giovannucci Edward L. , Hunter David J.
Published: May 2006

A single nucleotide polymorphism (SNP) at codon 72 of the p53 gene (Arg72Pro) alters the p53 protein structure and affects its activity. We investigated this SNP in relation to colorectal adenoma and cancer among men and women from case–control studies nested within the Nurses' Health Study, the Health Professionals Follow‐up Study and the Physicians' Health Study. Among 856 colorectal adenoma cases and 1,184 controls, we observed a modest association with p53 Arg72Pro genotype (multivariate odds ratio (OR) = 1.25, 95% confidence interval (CI) = 1.04–1.50 for Arg/Pro and Pro/Pro vs. Arg/Arg). This association did not vary by colorectal site or by sex. Among 442 colorectal cancer cases and 904 controls, we observed no significant overall association between p53 Arg72Pro genotype and colorectal cancer (multivariate OR = 1.14, 95% CI = 0.90–1.45). However, when colorectal site and sex was accounted for, the Pro carrier genotypes compared to Arg/Arg were associated with an increased risk of proximal colon cancers in women (multivariate OR = 2.59, 95% CI = 1.49–4.52) though not with distal colon or rectal cancers, while among men the same genotypes were associated with an increased risk of distal colon cancers (multivariate OR = 2.09, 95% CI = 1.28–3.40) but not proximal colon or rectal cancers. Our results suggest that Arg72Pro may play a role in the early stages of colorectal neoplasia and possibly in progression to invasive disease, depending on site and sex. © 2006 Wiley‐Liss, Inc.
Food intake and risk of squamous cell carcinoma of the skin in a community: The Nambour skin cancer cohort study
Authors: Hughes Maria Celia , van der Pols Jolieke C. , Marks Geoffrey C. , Green Adèle C.
Published: May 2006

There is some evidence that dietary factors may modify the risk of squamous cell carcinoma (SCC) of the skin, but the association between food intake and SCC has not been evaluated prospectively. We examined the association between food intake and SCC incidence among 1,056 randomly selected adults living in an Australian sub‐tropical community. Measurement‐error corrected estimates of intake in 15 food groups were defined from a validated food frequency questionnaire in 1992. Associations with SCC risk were assessed using Poisson and negative binomial regression to the persons affected and tumour counts, respectively, based on incident, histologically confirmed tumours occurring between 1992 and 2002. After multivariable adjustment, none of the food groups was significantly associated with SCC risk. Stratified analysis in participants with a past history of skin cancer showed a decreased risk of SCC tumours for high intakes of green leafy vegetables (RR = 0.45, 95% CI = 0.22–0.91; p for trend = 0.02) and an increased risk for high intake of unmodified dairy products (RR = 2.53, 95% CI: 1.15–5.54; p for trend = 0.03). Food intake was not associated with SCC risk in persons who had no past history of skin cancer. These findings suggest that consumption of green leafy vegetables may help prevent development of subsequent SCCs of the skin among people with previous skin cancer and that consumption of unmodified dairy products, such as whole milk, cheese and yoghurt, may increase SCC risk in susceptible persons. © 2006 Wiley‐Liss, Inc.
DNA mismatch repair as an effector for promoting phorbol ester‐induced apoptotic DNA damage and cell killing: Implications in tumor promotion
Authors: Lin Ching‐Tai , Lin Wei‐Hsin , Lee Kuan‐Der , Tzeng Pay‐Yu
Published: May 2006

Phorbol ester was known to activate protein kinase C (PKC) and exert numerous cellular effects, including proliferation, apoptosis, and oncogenic transformation. How phorbol ester stimulates both apoptosis and tumor promotion is not clear. Here DNA mismatch repair (MMR)‐proficient human colon cancer cells (DLD‐1+Ch2; hMSH6+) treated with 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) undergo rapid cell death, which is significantly abolished by staurosporine (PKC inhibitor) or antioxidant, compared with the paired MMR‐deficient (DLD‐1; hMSH6−) cells. Induction of reactive oxygen species (ROS) by TPA is shown to be one of downstream effectors required, but not sufficient, for cell killing as it is also observed in DLD‐1 cells. Strikingly, DLD‐1+Ch2 cells selected for resistance to TPA are found to lose the expression of hMSH6. Treatment of TPA‐resistant DLD‐1+Ch2 cells with 5‐aza‐2′‐deoxycytidine, not only restores hMSH6 expression but also resensitizes TPA‐resistant cells to TPA, suggesting that expression of hMSH6 is transcriptionally silenced by cytosine methylation confirmed directly by bisulfite sequencing. Knockdown hMSH6 or hPMS2 with siRNA in DLD‐1+Ch2 cells resulted in more resistant to TPA‐induced cell killing, further suggesting that MMR proteins involve in TPA or ROS‐induced cell killing. Results suggest that deficiency in MMR could promote tumorigenesis by inhibiting apoptotic responses to ROS‐mediated DNA damages as ROS are continuously produced as a byproduct of normal metabolism. © 2006 Wiley‐Liss, Inc.
Reduced incidence of cervical cancer in mothers of sons with allergic rhinoconjunctivitis, asthma or eczema
Authors: Ivansson Emma L. , Rasmussen Finn , Gyllensten Ulf B. , Magnusson Patrik K.E.
Published: May 2006

Because infection with human papillomavirus is a necessary cause of cervical cancer, it is likely that host immunological factors involved in defense against such infections are important for susceptibility to this cancer. By examining associations between allergy in sons and cervical cancer in their mothers, we aimed to test for genetic components involved in both allergy and cervical cancer development. Women born in Sweden between 1932 and 1960 with at least 1 son with medical records from military conscription examination were included in the study (N = 717,963). Among these women there were 41,910 in situ and 3,618 invasive cases of cervical cancer. Hazard ratios of in situ and invasive cervical cancer were estimated as functions of allergic rhinoconjunctivitis, asthma and eczema diagnoses in sons. Adjustment was made for the possible confounders: age, year of birth, education, socio‐economic index, geography, number of conscripted sons and total number of offspring. The risk of in situ and invasive cervical cancer was lower for women having sons diagnosed with hypersensitivity (allergic rhinoconjunctivitis, asthma or eczema). Fully adjusted hazard ratios for women with 1 hypersensitive son were for in situ 0.86 (95% CI 0.84–0.88) and for invasive cervical cancer 0.82 (95% CI 0.74–0.91). The protective effects were similar between the 3 allergic diagnoses and increased with number of sons with a diagnosis. There was no significant association between non‐cervical cancer in mothers and allergy in sons. These results strengthen the hypothesis that inherited immunological factors are important in determining risk of cervical cancer, probably by affecting mechanisms for viral persistence. © 2006 Wiley‐Liss, Inc.
BRAF and KRAS mutations in prostatic adenocarcinoma
Authors: Cho Nam‐Yun , Choi Minhee , Kim Baek‐Hee , Cho Yong‐Mee , Moon Kyung Chul , Kang Gyeong Hoon
Published: May 2006

Constitutive activation of the kinase cascade involving RAS, RAF, MEK and ERK is common to human cancers, and mutations of KRAS and BRAF are mutually exclusive and serve as alternatives to activate the RAS/RAF/ERK signaling pathway. RAS mutations are known to occur in prostate adenocarcinomas, but little is known about BRAF mutations in these tumors. In the present study, BRAF and KRAS mutations were characterized in 206 prostate adenocarcinomas by enhanced PCR‐RFLP and direct sequencing. The identified KRAS and BRAF mutations were then analyzed with respect to preoperative serum PSA levels, Gleason scores and tumor stages. Mutations in codon 600 of BRAF were identified in 21 (10.2%) of 206 prostate adenocarcinomas. KRAS mutations in codons 12 or 13 were found in 15 (7.3%) of 206 prostate adenocarcinomas. However, no tumor specimen contained both BRAF and KRAS mutations. Prostate adenocarcinomas with a BRAF mutation tended to show higher preoperative serum PSA levels, Gleason scores and tumor stages than prostate adenocarcinomas with a KRAS mutation. The results obtained show that BRAF mutations are as uncommon as KRAS mutations in prostate adenocarcinoma. Although BRAF and KRAS are members of the same RAS/ERK signaling pathway, prostate adenocarcinomas with a BRAF mutation showed clinicopathologic features that differed from those of prostate adenocarcinoma with a KRAS mutation. © 2006 Wiley‐Liss, Inc.
Melanocortin 1 receptor variants and skin cancer risk
Authors: Han Jiali , Kraft Peter , Colditz Graham A. , Wong Jason , Hunter David J.
Published: May 2006

Melanocortin 1 receptor (MC1R) gene variants are associated with red hair and fair skin color. We assessed the associations of common MC1R genotypes with the risks of 3 types of skin cancer simultaneously in a nested case–control study within the Nurses' Health Study (219 melanoma, 286 squamous cell carcinoma (SCC), and 300 basal cell carcinoma (BCC) cases, and 873 controls). We found that the 151Cys, 160Trp and 294His variants were significantly associated with red hair, fair skin color and childhood tanning tendency. The MC1R variants, especially the 151Cys variant, were associated with increased risks of the 3 types of skin cancer, after controlling for hair color, skin color and other skin cancer risk factors. Carriers of the 151Cys variant had an OR of 1.65 (95% CI, 1.04–2.59) for melanoma, 1.67 (1.12–2.49) for SCC and 1.56 (1.03–2.34) for BCC. Women with medium or olive skin color carrying 1 nonred hair color allele and 1 red hair color allele had the highest risk of melanoma. A similar interaction pattern was observed for red hair and carrying at least 1 red hair color allele on melanoma risk. We also observed that the 151Cys variant contributed additional melanoma risk amongred‐haired women. The information on MC1R status modestly improved the risk prediction; the increase was significant for melanoma and BCC (p, 0.004 and 0.05, respectively). These findings indicated that the effects of the MC1R variants on skin cancer risk were independent from self‐reported phenotypic pigmentation. © 2006 Wiley‐Liss, Inc.
Biological performance of a new β‐TCP/PLLA composite material for applications in spine surgery: In vitro and in vivo studies
Authors: Aunoble Stephane , Clément Denis , Frayssinet Patrick , Harmand Marie Francois , Le Huec Jean Charles
Published: May 2006

The objective of this research was to carry out an in vitro and in vivo study of the biological performance of PLLA/β‐TCP composite materials, to estimate the scope of their potential applications in bone surgery. Samples with increasing β‐TCP (0–60% w/w) contents were processed by injection molding. The in vitro study consisted of an evaluation of inflammatory potential by assaying the IL‐1α secreted by monocytes, and then cell proliferation (counting) and phenotype expression (PAL and I collagen) in human osteogenous cells. The in vivo study was carried out using cylindrical implants of composite materials composed of composite materials containing 0 or 60% β‐TCP and pure β‐TCP, respectively. The implants were inserted in femoral sites in rabbits, using the Kathagen protocol. Each animal received a 60% implant, with either a 0 or a 100% implant in the contralateral femur, so that the materials could be compared with one another. Five animals were examined for each material and implantation period, giving a total of 30 animals. This study showed that adding increasing percentages of β‐TCP to a lactic acid polymer matrix stimulated the proliferation of human osteogenous cells and synthesis of the extracellular bone matrix in a dose‐dependent manner. In vivo results indicate that, in comparison with pure PLA, tricalcium phosphate‐containing composite materials had faster degradation kinetics, caused less inflammatory reaction, and promoted contact osteogenesis. The composite material containing 60% β‐TCP demonstrated a similar performance to pure tricalcium phosphate bone grafts in terms of osteogenesis, and is apparently compatible with the production of intra‐osseous implants for situations representing high levels of mechanical strain. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Selectively crosslinked hyaluronic acid hydrogels for sustained release formulation of erythropoietin
Authors: Motokawa Keiko , Hahn Sei Kwang , Nakamura Teruo , Miyamoto Hajime , Shimoboji Tsuyoshi
Published: May 2006

A novel sustained release formulation of erythropoietin (EPO) was developed using hyaluronic acid (HA) hydrogels. For the preparation of HA hydrogels, adipic acid dihydrazide grafted HA (HA‐ADH) was synthesized and analyzed with 1H NMR. The degree of HA‐ADH modification was about 69%. EPO was in situ encapsulated into HA‐ADH hydrogels through a selective cross‐linking reaction of bis(sulfosuccinimidyl) suberate (BS3) to hydrazide group (pKa = 3.0) of HA‐ADH rather than to amine group (pKa > 9) of EPO. The denaturation of EPO during HA‐ADH hydrogel synthesis was drastically reduced with decreasing pH from 7.4 to 4.8. The specific reactivity of BS3 to hydrazide at pH = 4.8 might be due to its low pKa compared with that of amine. In vitro release of EPO in phosphate buffered saline at 37°C showed that EPO was released rapidly for 2 days and then slowly up to 4 days from HA‐ADH hydrogels. When the hydrogels were dried at 37°C for a day, however, longer release of EPO up to 3 weeks could be demonstrated. According to in vivo release test of EPO from HA‐ADH hydrogels in SD rats, elevated EPO concentration higher than 0.1 ng/mL could be maintained from 7 days up to 18 days depending on the preparation methods of HA‐ADH hydrogels. There was no adverse effect during and after HA‐ADH hydrogel implantation. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
AFM force spectroscopy of the fibrinogen adsorption process onto dental implants
Authors: Boukari Abdessamad , Francius Grégory , Hemmerlé Joseph
Published: May 2006

Protein binding to implants is governed by the physicochemical properties of the biomaterial surface. The adhesion of a protein onto a solid surface is nonspecific. The aim of this study was to assess the adsorption process of fibrinogen at two different dental implants. The first biomaterial has a sand‐blasted titanium surface, whereas the second one is covered by a calcium phosphate coating. After scanning electron microscopy and atomic force microscopy characterization of the implant surfaces, force spectroscopy has been used to determine the unbinding force of fibrinogen adsorbed at the two different substrates. Force‐measurement findings indicate that the detachment force of fibrinogen adsorbed onto both surfaces varies as a function of the interaction time. The mean strength of the unbinding forces increases with the interaction time (100 and 1000 ms, respectively). However, experimental data suggest that fibrinogen fixes to the two studied biomaterials by different mechanisms. Moreover, it appears that, after an interaction time of 1000 ms, the detachment force of the adsorbed protein is quite larger for the titanium surface than for the calcium phosphate coating. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Expression and regulation of resistin in osteoblasts and osteoclasts indicate a role in bone metabolism
Authors: Thommesen Liv , Stunes Astrid Kamilla , Monjo Marta , Grøsvik Kristin , Tamburstuen Margareth V. , Kjøbli Eli , Lyngstadaas Ståle Petter , Reseland Janne E. , Syversen Unni
Published: May 2006

The adipose tissue is the site of expression and secretion of a range of biologically active proteins, called adipokines, for example, leptin, adiponectin, and resistin. Leptin has previously been shown to be expressed in osteoblasts and to promote bone mineralization, whereas adiponectin expression is enhanced during osteoblast differentiation. In the present study we explored the possible role of resistin in bone metabolism. We found that resistin is expressed in murine preosteoclasts and preosteoblasts (RAW 264.7, MC3T3‐E1), in primary human bone marrow stem cells and in mature human osteoblasts. The expression of resistin mRNA in RAW 264.7 was increased during differentiation and seemed to be regulated through PKC‐ and PKA‐dependent mechanisms. Recombinant resistin increased the number of differentiated osteoclasts and stimulated NFκB promoter activity, indicating a role in osteoclastogenesis. Resistin also enhanced the proliferation of MC3T3‐E1 cells in a PKA and PKC‐dependent manner, but only weakly interfered with genes known to be upregulated during differentiation of MC3T3‐E1 into osteoblasts. All together, our results indicate that resistin may play a role in bone remodeling. J. Cell. Biochem. 99: 824–834, 2006. © 2006 Wiley‐Liss, Inc.
Unloading‐induced bone loss was suppressed in gold‐thioglucose treated mice
Authors: Hino K. , Nifuji A. , Morinobu M. , Tsuji K. , Ezura Y. , Nakashima K. , Yamamoto H. , Noda M.
Published: May 2006

Loss of mechanical stress causes bone loss. However, the mechanisms underlying the unloading‐induced bone loss are largely unknown. Here, we examined the effects of gold‐thioglucose (GTG) treatment, which destroys ventromedial hypothalamus (VMH), on unloading‐induced bone loss. Unloading reduced bone volume in control (saline‐treated) mice. Treatment with GTG‐reduced bone mass and in these GTG‐treated mice, unloading‐induced reduction in bone mass levels was not observed. Unloading reduced the levels of bone formation rate (BFR) and mineral apposition rate (MAR). GTG treatment also reduced these parameters and under this condition, unloading did not further reduce the levels of BFR and MAR. Unloading increased the levels of osteoclast number (Oc.N/BS) and osteoclast surface (Oc.S/BS). GTG treatment did not alter the basal levels of these bone resorption parameters. In contrast to control, GTG treatment suppressed unloading‐induced increase in the levels of Oc.N/BS and Oc.S/BS. Unloading reduced the levels of mRNA expression of the genes encoding osteocalcin, type I collagen and Cbfa1 in bone. In contrast, GTG treatment suppressed such unloading‐induced reduction of mRNA expression. Unloading also enhanced the levels of fat mass in bone marrow and mRNA expression of the genes encoding PPARgamma2, C/EBPalpha, and C/EBPbeta in bone. In GTG‐treated mice, unloading did not increase fat mass and the levels of fat‐related mRNA expression. These results indicated that GTG treatment suppressed unloading‐induced alteration in bone loss. J. Cell. Biochem. 99: 845–852, 2006. © 2006 Wiley‐Liss, Inc.
Plasma membrane destination of the classical Xenopus laevis progesterone receptor accelerates progesterone‐induced oocyte maturation
Authors: Martinez Silvana , Grandy Rodrigo , Pasten Pamela , Montecinos Hernán , Montecino Martín , Olate Juan , Hinrichs María Victoria
Published: May 2006

Xenopus laevis oocyte maturation is induced by the steroid hormone progesterone through a non‐genomic mechanism initiated at the cell membrane. Recently, two Xenopus oocyte progesterone receptors have been cloned; one is the classical progesterone receptor (xPR‐1) involved in genomic actions and the other a putative seven‐transmembrane‐G‐protein‐ couple receptor. Both receptors are postulated to be mediating the steroid‐induced maturation process in the frog oocyte. In this study, we tested the hypothesis that the classical progesterone receptor, associated to the oocyte plasma membrane, is participating in the reinitiation of the cell cycle. Addition of a myristoilation and palmytoilation signal at the amino terminus of xPR‐1 (mp xPR‐1), increased the amount of receptor associated to the oocyte plasma membrane and most importantly, significantly potentiated progesterone‐induced oocyte maturation sensitivity. These findings suggest that the classical xPR‐1, located at the plasma membrane, is mediating through a non‐genomic mechanism, the reinitiation of the meiotic cell cycle in the X. laevis oocyte. J. Cell. Biochem. 99: 853–859, 2006. © 2006 Wiley‐Liss, Inc.
Functional overexpression and characterization of human bradykinin subtype 2 receptor in insect cells using the baculovirus system
Authors: Shukla Arun Kumar , Haase Winfried , Reinhart Christoph , Michel Hartmut
Published: May 2006

Bradykinin exerts its actions via binding to B1 and B2 receptors (B1R and B2R), which are members of G protein‐coupled receptor superfamily. B2R is constitutively expressed in a variety of cells such as endothelial cells, vascular smooth muscle cells, and cardiomyocytes and it is an important drug target for the treatment of cardiovascular disorders. During this study, the human B2R was functionally overexpressed in insect cells using the baculovirus expression system. The maximum expression level in Sf9 cells under optimized condition was 10 pmol/mg. This corresponds to approximately 0.25 mg active receptor per liter culture. The recombinant receptor showed high affinity for its endogenous ligand bradykinin, similar to the B2R expressed in native tissues. Functional coupling of the recombinant receptor to the endogenous Gαs protein was demonstrated via cAMP release assay upon agonist stimulation. Confocal laser scanning microscopy and immunogold‐labeling experiment revealed that the recombinant B2R was mainly localized intracellularly and only a minor fraction of the recombinant receptor reached the plasma membrane. To our knowledge, this is the first report of high level expression of recombinant B2R in insect cells and provides a way for large scale production and structural characterization of this receptor. J. Cell. Biochem. 99: 868–877, 2006. © 2006 Wiley‐Liss, Inc.
Amyloid β oligomerization is induced by brain lipid rafts
Authors: Kim Sang‐Il , Yi Jae‐Sung , Ko Young‐Gyu
Published: May 2006

Detergent‐resistant lipid rafts are required for the generation of Aβ as they concentrate not only amyloid precursor protein (APP), but also the β‐ and γ‐secretase that convert APP to Aβ. Recently, Aβ has been shown to be oligomerized, which results in neuronal cytotoxicity and synaptic failure. In this study, we have demonstrated that Aβ oligomers appeared immediately after the incubation of Aβ with lipid rafts isolated from the brain tissues of rats, and were converted into few Aβ fibrils, even after longer periods of incubation. The oligomerization of Aβ was not abolished after the brain lipid rafts were treated with heat, or with protease K, implying that the lipid raft proteins were determined not to be prerequisites for Aβ oligomerization. The cholesterol present in the lipid rafts might not be essential to Aβ oligomerization because Aβ oligomerization was not prevented after the cholesterol was removed from the lipid rafts with methyl‐β‐cyclodextrin (MβCD). The Aβ oligomerization was accelerated by the application of lipid rafts isolated from ganglioside‐rich cells, C2C12 cells, whereas this was not observed with the lipid rafts isolated from ganglioside‐poor cells SK‐N‐MC and HeLa cells. In addition, lipid raft‐induced Aβ oligomerization was shown to be inhibited in CHO‐K1 cells which were defective with regard to ganglioside biosynthesis. This indicates that Aβ oligomerization requires gangliosides that are enriched in the lipid rafts. J. Cell. Biochem. 99: 878–889, 2006. © 2006 Wiley‐Liss, Inc.
CDC2L5, a Cdk‐like kinase with RS domain, interacts with the ASF/SF2‐associated protein p32 and affects splicing in vivo
Authors: Even Yasmine , Durieux Sandrine , Escande Marie‐Line , Lozano Jean Claude , Peaucellier Gérard , Weil Dominique , Genevière Anne‐Marie
Published: May 2006

The human CDC2L5 gene encodes a protein of unknown physiological function. This protein is closely related to the cyclin‐dependent kinase (Cdks) family and contains an arginine/serine‐rich (RS) domain. The Cdks were first identified as crucial regulators of cell‐cycle progression, more recently they were found to be involved in transcription and mRNA processing. RS domains are mainly present in proteins regulating pre‐mRNA splicing, suggesting CDC2L5 having a possible role in this process. In this study, we demonstrate that CDC2L5 is located in the nucleoplasm, at a higher concentration in speckles, the storage sites for splicing factors. Furthermore, this localization is dependent on the presence of the N‐terminal sequence including the RS domain. Then, we report that CDC2L5 directly interacts with the ASF/SF2‐associated protein p32, a protein involved in splicing regulation. Overexpression of CDC2L5 constructs disturbs constitutive splicing and switches alternative splice site selection in vivo. These results argue in favor of a functional role of the CDC2L5 kinase in splicing regulation. J. Cell. Biochem. 99: 890–904, 2006. © 2006 Wiley‐Liss, Inc.
2D representation of protein secondary structure sequences and its applications
Authors: Liu Liwei , Wang Tianming
Published: May 2006

In terms of the classification of the protein secondary structures, we propose a 2D representation of protein secondary structure sequences. The representation are used to display, analyze, and compare the secondary structure sequences. Based on this representation, we assign the structural class to the protein, and verify the advantage or disadvantage of the methods of predicted protein second structure. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1119–1124, 2006