bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative genome analysis of cortactin and HS1: the significance of the F-actin binding repeat domain
Authors: van Rossum Agnes GSH , Schuuring-Scholtes Ellen , van Buuren-van Seggelen Vera , Kluin Philip M , Schuuring Ed
Published: February 2005

Background

In human carcinomas, overexpression of cortactin correlates with poor prognosis. Cortactin is an F-actin-binding protein involved in cytoskeletal rearrangements and cell migration by promoting actin-related protein (Arp)2/3 mediated actin polymerization. It shares a high amino acid sequence and structural similarity to hematopoietic lineage cell-specific protein 1 (HS1) although their functions differ considerable. In this manuscript we describe the genomic organization of these two genes in a variety of species by a combination of cloning and database searches. Based on our analysis, we predict the genesis of the actin-binding repeat domain during evolution.

Results

Cortactin homologues exist in sponges, worms, shrimps, insects, urochordates, fishes, amphibians, birds and mammalians, whereas HS1 exists in vertebrates only, suggesting that both genes have been derived from an ancestor cortactin gene by duplication. In agreement with this, comparative genome analysis revealed very similar exon-intron structures and sequence homologies, especially over the regions that encode the characteristic highly conserved F-actin-binding repeat domain. Cortactin splice variants affecting this F-actin-binding domain were identified not only in mammalians, but also in amphibians, fishes and birds. In mammalians, cortactin is ubiquitously expressed except in hematopoietic cells, whereas HS1 is mainly expressed in hematopoietic cells. In accordance with their distinct tissue specificity, the putative promoter region of cortactin is different from HS1.

Conclusions

Comparative analysis of the genomic organization and amino acid sequences of cortactin and HS1 provides inside into their origin and evolution. Our analysis shows that both genes originated from a gene duplication event and subsequently HS1 lost two repeats, whereas cortactin gained one repeat. Our analysis genetically underscores the significance of the F-actin binding domain in cytoskeletal remodeling, which is of importance for the major role of HS1 in apoptosis and for cortactin in cell migration.
A class of models for analyzing GeneChip® gene expression analysis array data
Authors: Fan Wenhong , Pritchard Joel I , Olson James M , Khalid Najma , Zhao Lue Ping
Published: February 2005

Background

Various analytical methods exist that first quantify gene expression and then analyze differentially expressed genes from Affymetrix GeneChip® gene expression analysis array data. These methods differ in the choice of probe measure (quantification of probe hybridization), summarizing multiple probe intensities into a gene expression value, and analysis of differential gene expression. Research papers that describe these methods focus on performance, and how their approaches differ from others. To better understand the common features and differences between various methods, and to evaluate their impact on the results of gene expression analysis, we describe a class of models, referred to as generalized probe models (GPMs), which encompass various currently available methods.

Results

Using an empirical dataset, we compared different formulations of GPMs, and GPMs with three other commonly used methods, i.e. MAS 5.0, dChip, and RMA. The comparison shows that, on a genome-wide scale, different methods yield similar results if the same probe measures are chosen.

Conclusion

In this paper we present a general framework, i.e. GPMs, which encompasses various methods. GPMs permit the use of a wide range of probe measures and facilitate appropriate comparison between commonly used methods. We demonstrate that the dissimilar results stem primarily from different choice of probe measures, rather than other factors.
Response of SII cortex to ipsilateral, contralateral and bilateral flutter stimulation in the cat
Authors: Tommerdahl Mark , Simons Stephen B , Chiu Joannellyn S , Tannan Vinay , Favorov Oleg , Whitsel Barry
Published: February 2005

Background

A distinctive property of SII is that it is the first cortical stage of the somatosensory projection pathway that integrates information arising from both sides of the body. However, there is very little known about how inputs across the body mid-line are processed within SII.

Results

Optical intrinsic signal imaging was used to evaluate the response of primary somatosensory cortex (SI and SII in the same hemisphere) to 25 Hz sinusoidal vertical skin displacement stimulation ("skin flutter") applied contralaterally, ipsilaterally, and bilaterally to the central pads of the forepaws. A localized increase in absorbance in both SI and SII was evoked by both contralateral and bilateral flutter stimulation. Ipsilateral flutter stimulation evoked a localized increase in absorbance in SII, but not in SI. The SII region that responded with an increase in absorbance to ipsilateral stimulation was posterior to the region in which absorbance increased maximally in response to stimulation of the contralateral central pad. Additionally, in the posterior SII region that responded maximally to ipsilateral stimulation of the central pad, bilateral central pad stimulation approximated a linear summation of the SII responses to independent stimulation of the contralateral and ipsilateral central pads. Conversely, in anterior SII (the region that responded maximally to contralateral stimulation), bilateral stimulation was consistently less than the response evoked from the contralateral central pad.

Conclusions

The results indicate that two regions located at neighboring, but distinctly different A-P levels of the anterior ectosylvian gyrus process input from opposite sides of the body midline in very different ways. The results suggest that the SII cortex, in the cat, can be subdivided into at least two functionally distinct regions and that these functionally distinct regions demonstrate a laterality preference within SII.
Comparative analysis of mouse skeletal muscle fibre type composition and contractile responses to calcium channel blocker
Authors: Mänttäri Satu , Järvilehto Matti
Published: February 2005

Background

In this study, we examined the correlation between excitation-contraction coupling characteristics and skeletal muscle fibre type by (1) localizing the distribution of dihydropyridine receptor (DHPR) protein and (2) comparing the effect of DHPR blocker on muscles with different fibre type composition, in order to better understand the differences between contractile phenotypes of fibres and to explain the contradictory reports to date on the interaction of dihydropyridines with skeletal muscle isoform of DHPR.

Results

Histochemical experiments revealed that fluorophore conjugated dihydropyridines stain selectively the membranes of muscle fibres. The staining was most evident in type IIA fibres. The major fibre type in gluteus and femoris, revealed by mATPase staining, was IIA (45.0 and 38.1 %, respectively). In gastrocnemius the content of IIA fibres was 22.7 %. Contraction forces before and after the addition of blocker for the three muscles investigated were: gluteus 0.075 ± 0.017 N vs. 0.052 ± 0.011 N, femoris 0.045 ± 0.005 N vs. 0.033 ± 0.005 N and gastrocnemius 0.089 ± 0.016 N vs. 0.075 ± 0.014 N, respectively. The attenuation of contraction force proportional to the cross-sectional area of the muscle was significantly (P = 0.023) higher in gluteus (28.3 ± 3.5 %) and femoris (27.6 ± 3.2 %) as compared to gastrocnemius (16.1 ± 2.5 %). However, no significant change in the control measurements was observed ruling out the possibility of fatigue.

Conclusion

The results indicate that the attenuation of the contraction force was largest in muscles with a high percentage of type IIA fibres. This supports our finding that the abundance of dihydropyridine receptors of IIA fibres outnumbers that in the other fibre types. The present data show that the correlation of density of dihydropyridine receptors can be one of the important factors influencing the overall contractile properties of the muscle and for its part explain the contradictory results of previous studies on coupling process.
Diagnosis and treatment of carotid body paraganglioma: 21 years of experience at a clinical center of Serbia
Authors: Davidovic Lazar B , Djukic Vojko B , Vasic Dragan M , Sindjelic Radomir P , Duvnjak Stevo N
Published: February 2005

Background

The carotid body paraganglioma (chemodectoma) is a relatively rare neoplasm of obscure origin. These are usually benign and commonly present as asymptomatic cervical mass.

Patients and methods

Records of 12 patients (9 female and 3 male) with carotid body tumors treated between 1982 and 2003, treated at our center were retrospectively reviewed. Data on classification, clinical presentation, and surgical treatment were extracted from the case records. Surgical complications and treatment outcome were noted and survival was calculated by actuarial method. The literature on carotid body paraganglioma was reviewed.

Results

The average age of the patients was 52 years (range 30–78 years). Eight of these cases presented as a large asymptomatic non-tender neck mass, and two each presented with dysphagia, and hoarseness of voice. As per Shamblin classification seven of tumors were type II and 5 were types III. In 7 cases subadventitial tumor excision was performed, while in 5 associated resection of both external and internal carotid arteries was carried out. The artery was repaired by end-to-end anastomosis in one case, with Dacron graft in one case, and with saphenous vein graft in 3 cases. There was no operative mortality. After a mean follow-up of 6.2 years (range 6 months to 20 years), there were no signs of tumor recurrence in any of the cases.

Conclusions

Surgical excision is the treatment of choice for carotid body paragangliomas although radiation therapy is an option for patients who are not ideal candidates for surgery. For the tumors that are in intimate contact with carotid arteries, the treatment by vascular surgeon is recommended.
Propagated repolarization of simulated action potentials in cardiac muscle and smooth muscle
Authors: Sperelakis Nicholas , Ramasamy Lakshminarayanan , Kalloor Bijoy
Published: February 2005

Background

Propagation of repolarization is a phenomenon that occurs in cardiac muscle. We wanted to test whether this phenomenon would also occur in our model of simulated action potentials (APs) of cardiac muscle (CM) and smooth muscle (SM) generated with the PSpice program.

Methods

A linear chain of 5 cells was used, with intracellular stimulation of cell #1 for the antegrade propagation and of cell #5 for the retrograde propagation. The hyperpolarizing stimulus parameters applied for termination of the AP in cell #5 were varied over a wide range in order to generate strength / duration (S/D) curves. Because it was not possible to insert a second "black box" (voltage-controlled current source) into the basic units representing segments of excitable membrane that would allow the cells to respond to small hyperpolarizing voltages, gap-junction (g.j.) channels had to be inserted between the cells, represented by inserting a resistor (Rgj) across the four cell junctions.

Results

Application of sufficient hyperpolarizing current to cell #5 to bring its membrane potential (Vm) to within the range of the sigmoidal curve of the Na+ conductance (CM) or Ca++ conductance (SM) terminated the AP in cell #5 in an all-or-none fashion. If there were no g.j. channels (Rgj = ∞), then only cell #5 repolarized to its stable resting potential (RP; -80 mV for CM and -55 mV for SM). The positive junctional cleft potential (VJC) produced only a small hyperpolarization of cell #4. However, if many g.j. channels were inserted, more hyperpolarizing current was required (for a constant duration) to repolarize cell #5, but repolarization then propagated into cells 4, 3, 2, and 1. When duration of the pulses was varied, a typical S/D curve, characteristic of excitable membranes, was produced. The chronaxie measured from the S/D curve was about 1.0 ms, similar to that obtained for muscle membranes.

Conclusions

These experiments demonstrate that normal antegrade propagation of excitation can occur in the complete absence of g.j. channels, and therefore no low-resistance pathways between cells, by the electric field (negative VJC) developed in the narrow junctional clefts. Because it was not possible to insert a second black-box into the basic units that would allow the cells to respond to small hyperpolarizing voltages, only cell #5 (the cell injected with hyperpolarizing pulses) repolarized in an all-or-none manner. But addition of many g.j. channels allowed repolarization to propagate in a retrograde direction over all 5 cells.
Simian immunodeficiency virus (SIV) envelope quasispecies transmission and evolution in infant rhesus macaques after oral challenge with uncloned SIVmac251: increased diversity is associated with neutralizing antibodies and improved survival in previously immunized animals
Authors: Greenier Jennifer L , Van Rompay Koen KA , Montefiori David , Earl Patricia , Moss Bernard , Marthas Marta L
Published: February 2005

Background

Oral infection of infant macaques with simian immunodeficiency virus (SIV) is a useful animal model to test interventions to reduce postnatal HIV transmission via breast-feeding. We previously demonstrated that immunization of infant rhesus macaques with either modified vaccinia virus Ankara (MVA) expressing SIV Gag, Pol and Env, or live-attenuated SIVmac1A11 resulted in lower viremia and longer survival compared to unimmunized controls after oral challenge with virulent SIVmac251 (Van Rompay et al., J. Virology 77:179–190, 2003). Here we evaluate the impact of these vaccines on oral transmission and evolution of SIV envelope variants.

Results

Limiting dilution analysis of SIV RNA followed by heteroduplex mobility assays of the V1–V2 envelope (env) region revealed two major env variants in the uncloned SIVmac251 inoculum. Plasma sampled from all infants 1 week after challenge contained heterogeneous SIV env populations including one or both of the most common env variants in the virus inoculum; no consistent differences in patterns of env variants were found between vaccinated and unvaccinated infants. However, SIV env variant populations diverged in most vaccinated monkeys 3 to 5 months after challenge, in association with the development of neutralizing antibodies.

Conclusions

These patterns of viral envelope diversity, immune responses and disease course in SIV-infected infant macaques are similar to observations in HIV-infected children, and underscore the relevance of this pediatric animal model. The results also support the concept that neonatal immunization with HIV vaccines might modulate disease progression in infants infected with HIV by breast-feeding.
Psychiatric morbidity of overseas patients in inner London: A hospital based study
Authors: Carranza Fredy J , Parshall Alice M
Published: February 2005

Background

Evaluation of the referral, admission, treatment, and outcome of overseas patients admitted to a psychiatric hospital in central London. Ethical, legal and economic implications, and the involvement of consulates in the admission process, are discussed.

Method

Assessment and review of overseas patients admitted between 1 January 1999 and 31 December 1999. Non-parametric statistical tests were used, and relevant outcomes described.

Results

19% of admissions were overseas patients. Mean age was 38 years. 90% were unattached; 84% were white, 71% from European countries. 45% spoke fluent English. Differences in socio-economic status between home country and England were found. 74% were unwell on arrival; 65% travelled to England as tourists.

65% of admissions came via the police. 32% had been ill for more than one year before admission; 68% had psychiatric history. 77% were admitted and 48% discharged under section of the Mental Health Act. 74% had psychotic disorders, all of them with positive symptoms. 55% showed little to moderate improvement in mental state; 10% were on Enhanced Care Programme Approach. Relatives of 48% of patients were contacted.

The Hospital repatriated 52% of patients; the Mental Health Team followed up 13% of those discharged. The average length of admission was 43.4 days (range 1–365). Total cost of admissions was GBP350, 600 ($577, 490); average individual cost was GBP11, 116 (range GBP200-81, 000).

Conclusions

Mentally ill overseas individuals are a vulnerable group that need recognition by health organisations to adapt current practice to better serve their needs. The involvement of consulates needs further evaluation.
A DNA microarray survey of gene expression in normal human tissues
Authors: Shyamsundar Radha , Kim Young H , Higgins John P , Montgomery Kelli , Jorden Michelle , Sethuraman Anand , van de Rijn Matt , Botstein David , Brown Patrick O , Pollack Jonathan R
Published: February 2005

Background

Numerous studies have used DNA microarrays to survey gene expression in cancer and other disease states. Comparatively little is known about the genes expressed across the gamut of normal human tissues. Systematic studies of global gene-expression patterns, by linking variation in the expression of specific genes to phenotypic variation in the cells or tissues in which they are expressed, provide clues to the molecular organization of diverse cells and to the potential roles of the genes.

Results

Here we describe a systematic survey of gene expression in 115 human tissue samples representing 35 different tissue types, using cDNA microarrays representing approximately 26,000 different human genes. Unsupervised hierarchical cluster analysis of the gene-expression patterns in these tissues identified clusters of genes with related biological functions and grouped the tissue specimens in a pattern that reflected their anatomic locations, cellular compositions or physiologic functions. In unsupervised and supervised analyses, tissue-specific patterns of gene expression were readily discernable. By comparative hybridization to normal genomic DNA, we were also able to estimate transcript abundances for expressed genes.

Conclusions

Our dataset provides a baseline for comparison to diseased tissues, and will aid in the identification of tissue-specific functions. In addition, our analysis identifies potential molecular markers for detection of injury to specific organs and tissues, and provides a foundation for selection of potential targets for selective anticancer therapy.
Phase I Pharmacokinetic and Pharmacodynamic Study of Weekly 1-Hour and 24-Hour Infusion BMS-214662, a Farnesyltransferase Inhibitor, in Patients With Advanced Solid Tumors
Authors: Tabernero Josep , Rojo Fredy , Marimón Irene , Voi Maurizio , Albanell Joan , Guix Marta , Vázquez Federico , Carulla Joan , Cooper Michael , Andreu Jordi , Van Vreckem Anne , Bellmunt Joaquim , Manne Veeraswamy , Manning James A. , Garrido Carmen , Felip Enriqueta , del Campo Josep Maria , García Mónica , Valverde Sonia , Baselga José
Published: February 2005

Purpose

BMS-214662 is a potent, nonpeptide, small molecule inhibitor of human farnesyltransferase (FT). We have conducted a phase I pharmacokinetic (PK) and pharmacodynamic study of BMS-214662 administered intravenously weekly with 1- and 24-hour infusions. The objectives were to determine the dose-limiting toxicities and the recommended dose (RD), to describe PKs, and to evaluate the relationships between BMS-214662 exposure, FT inhibition, downstream signaling, and induction of apoptosis in tumor samples.

Patients and Methods

Patients with advanced solid tumors and adequate organ function were eligible. The dose was escalated according to a modified Fibonacci schedule.

Results

BMS-214662 was escalated from 56 to 278 mg/m2 in 37 patients in the 1-hour schedule, and from 84 to 492 mg/m2 in 31 patients in the 24-hour schedule. Dose-limiting toxicities included gastrointestinal and renal events. The RDs were 209 mg/m2 and 275 mg/m2 in the 1- and 24-hour schedules, respectively. Five patients (three with breast, one with gastric, and one with renal cell cancer) had clinical benefit from treatment. BMS-214662 exhibited linear PKs with area under the concentration-time curves at the RDs of 27 and 32 μM × h in the 1- and 24-hour schedules, respectively. The pattern of FT inhibition in peripheral-blood mononuclear cells at the RDs was different in the two schedules: high (> 80%) but short-lived (≤ 6 hours) in the 1-hour infusion and moderate (> 40%) but long-lived (24 hours) in the 24-hour infusion. BMS-214662 induced apoptosis in tumors but did not inhibit MAPK signaling.

Conclusion

BMS-214662 can be safely delivered in both the 1-hour and 24-hour infusions at biologically active doses, with the preclinical, PK, and pharmacodynamic profiles favoring the 24-hour schedule.
Neoadjuvant Trastuzumab Induces Apoptosis in Primary Breast Cancers
Authors: Mohsin Syed K. , Weiss Heidi L. , Gutierrez M. Carolina , Chamness Gary C. , Schiff Rachel , DiGiovanna Michael P. , Wang Chun-Xia , Hilsenbeck Susan G. , Osborne C. Kent , Allred D. Craig , Elledge Richard , Chang Jenny C.
Published: February 2005

Purpose

Greater understanding of the cellular response in trastuzumab-treated patients will provide insight into the clinical management of patients.

Patients and Methods

We performed a neoadjuvant trial in 35 patients with locally advanced HER-2/neu overexpressing breast cancers who received weekly trastuzumab given as a single agent for the first 3 weeks, followed by a combination of trastuzumab and docetaxel for 12 weeks before surgery. Sequential core biopsies were taken at baseline and within weeks 1 and 3 after the first dose of trastuzumab. Clinical response to trastuzumab was assessed by tumor measurements on day 22 before chemotherapy. Core biopsies were assessed by immunohistochemistry for cell cycle and proliferation (Ki67, p27, phosphorylated [p] -MAPK), apoptosis and survival (apoptotic index, p-Akt), epidermal growth factor receptor, and total and p-HER-2.

Results

There was early tumor regression with a median decrease of −20.0% (range. 0% to 60.4%) after only 3 weeks of trastuzumab, and eight patients (23%) had a partial response. Consistent with the clinical regressions, apoptosis was significantly induced (median increase from 3.5% to 4.7%; P = .006) within week 1, a 35% increase above baseline. No significant change in epidermal growth factor receptor score was observed in week 1, without changes in total or p-HER-2 expression. Tumors with high baseline Ki67 were less likely to respond (P = .02).

Conclusion

In primary breast cancers, trastuzumab substantially induces apoptosis, providing a molecular explanation for both its therapeutic efficacy and its successful combination with cytotoxic chemotherapy.
Randomized Phase II Study of Two Gemcitabine Schedules for Patients With Impaired Performance Status (Karnofsky performance status ≤ 70) and Advanced Non–Small-Cell Lung Cancer
Authors: Baka S. , Ashcroft L. , Anderson H. , Lind M. , Burt P. , Stout R. , Dowd I. , Smith D. , Lorigan P. , Thatcher N.
Published: February 2005

Purpose

This randomized phase II study compared two treatment schedules of gemcitabine in patients with non–small-cell lung cancer (NSCLC) and impaired Karnofsky performance status (KP). Primary objectives were to record changes from baseline KP and to assess symptom palliation. Secondary objectives were overall survival, tumor response, and toxicity.

Patients and Methods

Patients with stage IIIb and IV NSCLC and KP ≤ 70 were randomly assigned to receive gemcitabine 1,000 mg/m2on days 1, 8, and 15 of each 28-day cycle (3w4) or gemcitabine 1,500 mg/m2on days 1 and 8 of each 21-day cycle (2w3), both for up to six cycles. KP, toxicity, and SS14 lung cancer specific questions were recorded before each cycle of treatment. Response was evaluated 4 weeks after the last cycle.

Results

One hundred seventy-four patients were enrolled. There was significant early attrition due to disease progression; only 61.5% of patients were alive at 2 months. There was a significant improvement in KP from baseline to pre–cycle 3 in both arms, with a trend in favor of the 3w4 regimen for duration and faster onset of improvement. Eight of the 17 quality-of-life (QOL) variables assessed showed an improvement of more than 10% between baseline and the start of the third cycle of treatment. Response rate, survival, and duration were similar in both arms.

Conclusion

There was no significant difference between the two schedules examined in terms of improvement in KP or QOL, but there seemed to be a trend in favor of the 3w4 schedule.
Predictive and Prognostic Impact of Epidermal Growth Factor Receptor Mutation in Non–Small-Cell Lung Cancer Patients Treated With Gefitinib
Authors: Han Sae-Won , Kim Tae-You , Hwang Pil Gyu , Jeong Soohyun , Kim Jeongmi , Choi In Sil , Oh Do-Youn , Kim Jee Hyun , Kim Dong-Wan , Chung Doo Hyun , Im Seock-Ah , Kim Young Tae , Lee Jong Seok , Heo Dae Seog , Bang Yung-Jue , Kim Noe Kyeong
Published: February 2005

Purpose

This study was undertaken to investigate the effects of epidermal growth factor receptor (EGFR) mutation and its downstream signaling on response and survival in non–small-cell lung cancer (NSCLC) patients treated with gefitinib.

Patients and Methods

For 90 consecutive NSCLC patients who had received gefitinib, EGFR mutation was analyzed by DNA sequencing of exons 18, 19, 21, and 23 in the EGFR tyrosine kinase domain. Expressions of phosphorylated (p) -Akt and p-Erk were determined via immunohistochemistry. Response rate, time to progression (TTP), and overall survival were compared between each group according to EGFR mutation, as well as p-Akt and p-Erk expression.

Results

Seventeen patients (18.9%; 95% CI, 10.8 to 27.0) harbored EGFR mutations. These mutations include deletions in exon 19 in seven patients, L858R in six patients, G719A in three patients, and a novel A859T in one patient. Response rate in patients with EGFR mutation was 64.7% (11 of 17 patients; 95% CI, 42.0 to 87.4), in contrast to 13.7% (10 of 73 patients; 95% CI, 5.8 to 21.6) in patients without mutation (P < .001). Moreover, these 17 patients with EGFR mutation had significantly prolonged TTP (21.7 v 1.8 months; P < .001) and overall survival (30.5 v 6.6 months; P < .001) compared with the remaining 73 patients without mutation. Although no significant correlation was detected between EGFR mutation and expressions of p-Akt or p-Erk, p-Akt overexpression was associated with prolonged TTP in patients with EGFR mutation.

Conclusion

Our data further support the importance of EGFR mutation with regard to gefitinib sensitivity. In addition to its predictive role, EGFR mutation confers significant survival benefits on NSCLC patients treated with gefitinib.
Safety and Efficacy of Two Different Doses of Capecitabine in the Treatment of Advanced Breast Cancer in Older Women
Authors: Bajetta Emilio , Procopio Giuseppe , Celio Luigi , Gattinoni Luca , Della Torre Silvia , Mariani Luigi , Catena Laura , Ricotta Riccardo , Longarini Raffaella , Zilembo Nicoletta , Buzzoni Roberto
Published: February 2005

Purpose

To evaluate the safety and efficacy of capecitabine in older women with advanced breast cancer.

Patients and Methods

Seventy-three eligible patients (median age, 73 years; range, 65 to 89 years) were enrolled. The first 30 patients received oral capecitabine 1,250 mg/m2 twice daily on days 1 to 14 every 21 days. Due to the occurrence of two toxic deaths, capecitabine 1,000 mg/m2 twice daily was given to the subsequent 43 patients.

Results

All patients were assessable for safety and efficacy. A total of 351 treatment cycles were administered (median, six per patient; range, one to eight cycles). Dose reductions due to toxicities were required in 30% of patients in the standard-dose group, but capecitabine was given without a dose reduction to 95% of patients in the low-dose group. Capecitabine demonstrated a favorable safety profile. The overall incidence of grade 3/4 toxicities was low: the most common events reported in ≤ 10% of the patients were fatigue, diarrhea, dyspnea, and nausea. In the standard-dose group, the response rate was 36.7% (95% CI, 19.9% to 56.1%). An additional seven patients had disease stabilization at ≥ 24 weeks. In the low-dose group, the response rate was 34.9% (95% CI, 21% to 50.9%). An additional 15 patients had prolonged stabilization. The median time to disease progression was 4 months in either group.

Conclusion

This study shows that capecitabine is safe and effective in the elderly breast cancer patient. Based on the overall results, the capecitabine dose of 1,000 mg/m2 twice daily merits consideration as “standard” for older patients who do not have severely impaired renal function.
Vascular and Neoplastic Risk in a Large Cohort of Patients With Polycythemia Vera
Authors: Marchioli Roberto , Finazzi Guido , Landolfi Raffaele , Kutti Jack , Gisslinger Heinz , Patrono Carlo , Marilus Raphael , Villegas Ana , Tognoni Gianni , Barbui Tiziano
Published: February 2005

Purpose

The clinical course of polycythemia vera is often complicated by thrombosis as well as by the possible transition to myeloid metaplasia with myelofibrosis or acute myeloid leukemia. The aim of this study was to assess the rate of these complications in subjects receiving currently recommended treatments.

Patients and Methods

Overall, 1,638 patients from 12 countries were enrolled onto a large, prospective multicenter project aimed at describing the clinical history of polycythemia vera for the following outcomes: survival, the cumulative rate of cardiovascular death and thrombosis, the cumulative rate of leukemia, myelodysplasia, and myelofibrosis. The mean duration of the disease at entry and the duration of the follow-up were 4.9 and 2.7 years, respectively.

Results

The overall mortality rate of 3.7 deaths per 100 persons per year resulted from a moderate risk of cardiovascular death and a high risk of death from noncardiovascular causes (mainly hematologic transformations). Age older than 65 years and a positive history of thrombosis were the most important predictors of cardiovascular events. Antiplatelet therapy, but not cytoreductive treatment, was significantly associated with a lower risk of cardiovascular events. We found a consistent association between age and risk of leukemia, and between duration of the disease with risk of myelofibrosis.

Conclusion

The European Collaboration on Low-Dose Aspirin in Polycythemia Vera study documents that large international collaborative studies are feasible in this field, in which few epidemiologic data are available. The persistently high mortality rate from hematologic malignancies characterizes the unmet therapeutic need of polycythemic patients and suggests a priority for future studies in this disease.
The Vascular Endothelial Growth Factor (VEGF)/VEGF Receptor 2 Pathway Is Critical for Blood Vessel Survival in Corpora Lutea of Pregnancy in the Rodent
Authors: Pauli Samuel A. , Tang Hongyan , Wang Jeff , Bohlen Peter , Posser Robert , Hartman Tipton , Sauer Mark V. , Kitajewski Jan , Zimmermann Ralf C.
Published: February 2005

The vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR-2) pathway regulates proliferation, survival, and permeability of vasculature. This pathway is active during the formation of a corpus luteum, a highly vascularized, endocrine organ with a short life span during the nonpregnant state. In the pregnant state, the life span of corpora lutea is much longer because they play a critical role in supporting pregnancy development. We hypothesized that the VEGF/VEGFR-2 pathway plays a critical role in regulating angiogenic events in the corpora lutea of pregnancy. Injection of the neutralizing anti-VEGFR-2 antibody DC101 (ImClone Systems, Inc., New York, NY) on embryonic d 3.5 (preimplantation) or 6.5 (postimplantation) disrupts function of the corpora lutea of pregnancy in CD1 mice, as evidenced by a decrease in organ size, regression of luteal vessels, and a fall in progesterone secretion within 24 h postinjection. Inhibition of the VEGFR-2 caused removal of endothelial cells, mostly through endothelial cell detachment from the vascular basement membrane. Luteal steroid-producing epithelial cells were eliminated through apoptosis secondary to vasculature becoming dysfunctional. Disruption of luteal function caused arrest of embryonic development. The effect of antibody is specific to the ovary, because pregnancy progresses normally in ovariectomized, progesterone-replaced animals treated with anti-VEGFR-2 antibody. Embryonic blood vessels were not affected directly by the antibody, because it did not reach the embryo. Administration of an antibody against VE-cadherin (E4G10), which specifically blocks endothelial proliferation, did not disrupt luteal function and pregnancy development. Thus, VEGFR-2-mediated endothelial cell signals are critical to maintain functionality of luteal blood vessels during pregnancy. Potential clinical applications of inhibitors of the VEGF/VEGFR-2 pathway include emergency contraception and medical treatment of ectopic and abnormal intrauterine pregnancies.
Western Diet Modulates Insulin Signaling, c-Jun N-Terminal Kinase Activity, and Insulin Receptor Substrate-1ser307 Phosphorylation in a Tissue-Specific Fashion
Authors: Prada Patrícia Oliveira , Zecchin Henrique Gottardello , Gasparetti Alessandra Lia , Torsoni Márcio Alberto , Ueno Mirian , Hirata Aparecida Emiko , Corezola do Amaral Maria Esméria , Höer Nelci Fenalti , Boschero Antonio Carlos , Saad Mario José Abdalla
Published: February 2005

The mechanisms by which diet-induced obesity is associated with insulin resistance are not well established, and no study has until now integrated, in a temporal manner, functional insulin action data with insulin signaling in key insulin-sensitive tissues, including the hypothalamus. In this study, we evaluated the regulation of insulin sensitivity by hyperinsulinemic-euglycemic clamp procedures and insulin signaling, c-jun N-terminal kinase (JNK) activation and insulin receptor substrate (IRS)-1ser307 phosphorylation in liver, muscle, adipose tissue, and hypothalamus, by immunoprecipitation and immunoblotting, in rats fed on a Western diet (WD) or control diet for 10 or 30 d. WD increased visceral adiposity, serum triacylglycerol, and insulin levels and reduced whole-body glucose use. After 10 d of WD (WD10) there was a decrease in IRS-1/phosphatidylinositol 3-kinase/protein kinase B pathway in hypothalamus and muscle, associated with an attenuation of the anorexigenic effect of insulin in the former and reduced glucose transport in the latter. In WD10, there was an increased glucose transport in adipose tissue in parallel to increased insulin signaling in this tissue. After 30 d of WD, insulin was less effective in suppressing hepatic glucose production, and this was associated with a decrease in insulin signaling in the liver. JNK activity and IRS-1ser307 phosphorylation were higher in insulin-resistant tissues. In summary, the insulin resistance induced by WD is tissue specific and installs first in hypothalamus and muscle and later in liver, accompanied by activation of JNK and IRS-1ser307 phosphorylation. The impairment of the insulin signaling in these tissues, but not in adipose tissue, may lead to increased adiposity and insulin resistance in the WD rats.
Androgens and Postmeiotic Germ Cells Regulate Claudin-11 Expression in Rat Sertoli Cells
Authors: Florin Anne , Maire Magali , Bozec Aline , Hellani Ali , Chater Sonia , Bars Remi , Chuzel Franck , Benahmed Mohamed
Published: February 2005

In the present study we investigated whether fetal exposure to flutamide affected messenger and protein levels of claudin-11, a key Sertoli cell factor in the establishment of the hemotesticular barrier, at the time of two key events of postnatal testis development: 1) before puberty (postnatal d 14) during the establishment of the hemotesticular barrier, and 2) at the adult age (postnatal d 90) at the time of full spermatogenesis. The data obtained show that claudin-11 expression was inhibited in prepubertal rat testes exposed in utero to 2 and 10 mg/kg·d flutamide. However, in adult testes, the inhibition was observed only with 2, and not with 10, mg/kg·d of the antiandrogen. It is shown here that these differences between prepubertal and adult testes could be related to dual and opposed regulation of claudin-11 expression resulting from positive control by androgens and an inhibitory effect of postmeiotic germ cells. Indeed, testosterone is shown to stimulate claudin-11 expression in cultured Sertoli cells in a dose- and time-dependent manner (maximum effect with 0.06 μm after 72 h of treatment). In contrast, postmeiotic germ cells potentially exert a negative effect on claudin-11 expression, because adult rat testes depleted in spermatids (after local irradiation) displayed increased claudin-11 expression, whereas in a model of cocultured Sertoli and germ cells, spermatids, but not spermatocytes, inhibited claudin-11 expression. The apparent absence of claudin-11 expression changes in adult rat testes exposed to 10 mg/kg·d flutamide therefore could result from the antagonistic effects of 1) the inhibitory action of the antiandrogen and 2) the stimulatory effect of the apoptotic germ cells on claudin-11 expression. Together, due to the key role of claudin-11 in the hemotesticular barrier, the present findings suggest that such regulatory mechanisms may potentially affect this barrier (re)modeling during spermatogenesis.
Role of the Endothelin-1 System in the Luteolytic Process of Pseudopregnant Rabbits
Authors: Boiti Cristiano , Guelfi Gabriella , Brecchia Gabriele , Dall’Aglio Cecilia , Ceccarelli Piero , Maranesi Margherita , Mariottini Chiara , Zampini Danilo , Gobbetti Anna , Zerani Massimo
Published: February 2005

The aim of this study was to better understand the role of the endothelin-1 (ET-1) system in the process of controlling the corpora lutea (CL) life span in rabbits. ET-1 (10 μg iv) administration at d 9 and 12 of pseudopregnancy induced a functional luteolysis within 24 h of injection, but it was ineffective at both d 4 and 6. Pretreatments with Bosentan, a dual ETA/ETB receptor antagonist, or cyclooxygenase (COX) inhibitor blocked the luteolytic action of ET-1 but not that induced by prostaglandin F2α (PGF2α). In CL cultured in vitro, ET-1 increased (P ≤ 0.01) both PGF2α production and luteal nitric oxide synthase activity but decreased (P ≤ 0.01) progesterone release. Addition of ETA receptor antagonist BQ123 or COX inhibitor blocked the ET-1 luteolytic effects. Positive staining for ET-1 receptors was localized in ovarian blood vessels, granulosa cells of large follicles, and luteal cells. Immunoblot analysis of ET-1 receptor protein revealed a strong band of approximately 48 kDa in d-9 CL. Up to d 6 of pseudopregnancy, ET-1 mRNA abundance in CL was poorly expressed but then increased (P ≤ 0.01) at d 9 and 13. ETA-receptor transcript increased (P ≤ 0.01) at d 6, remained at the same level up to d 13, and then declined to the lowest (P ≤ 0.01) levels at d 22. ETB-receptor mRNA increased (P ≤ 0.01) throughout the late-luteal stage from d 13 up to d 18. Our data suggest that the luteolytic action of ET-1 may be a result of PGF2α synthesis from both luteal and accessory cells, via the COX pathways.
erbB-1 and erbB-4 Receptors Act in Concert to Facilitate Female Sexual Development and Mature Reproductive Function
Authors: Prevot Vincent , Lomniczi Alejandro , Corfas Gabriel , Ojeda Sergio R.
Published: February 2005

Glial erbB-1 and erbB-4 receptors are key components of the process by which neuroendocrine glial cells control LHRH secretion and the onset of female puberty. We now provide evidence that these two signaling systems work in a coordinated fashion to control reproductive function. To generate animals carrying functionally impaired erbB-1 and erbB-4 receptors, we crossed Waved 2 (Wa-2+/+) mice harboring a point mutation of the erbB-1 receptor with mice expressing a dominant-negative erbB-4 receptor in astrocytes. In comparison to single-deficient mice, double-mutant animals exhibited a further delay in the onset of puberty and a strikingly diminished adult reproductive capacity. Ligand-dependent erbB receptor phosphorylation and erbB-mediated MAPK (ERK 1/2) phosphorylation were impaired in mutant astrocytes. Wa-2+/+ or double-mutant astrocytes failed to respond to TGFα with production of prostaglandin E2, one of the factors mediating the stimulatory effect of astroglial erbB receptor activation on LHRH release. Medium conditioned by Wa-2+/+ or double-mutant astrocytes treated with TGFα failed to stimulate LHRH release from GT1–7 cells. The LH response to ovariectomy was significantly attenuated in mutant mice in comparison with wild-type controls. Although the Wa-2 mutation affects all cells bearing erbB-1 receptors, these results suggest that a major defect underlying the reproductive defects of animals with impaired erbB signaling is a decreased ability of glial cells to stimulate LHRH release. Thus, a coordinated involvement of erbB-1 and erbB-4 signaling systems is required for the normalcy of sexual development and the maintenance of mature female reproductive function.
Regulation of Sertoli-Germ Cell Adherens Junction Dynamics via Changes in Protein-Protein Interactions of the N-Cadherin-β-Catenin Protein Complex which Are Possibly Mediated by c-Src and Myotubularin-Related Protein 2: An in Vivo Study Using an Androgen Suppression Model
Authors: Zhang Jiayi , Wong Ching-hang , Xia Weiliang , Mruk Dolores D. , Lee Nikki P. Y. , Lee Will M. , Cheng C. Yan
Published: February 2005

Using a well characterized model of cell-cell actin-based adherens junction (AJ) disruption by suppressing the intratesticular testosterone level in adult rats with testosterone-estradiol implants, we have confirmed earlier findings that Sertoli-germ cell AJ dynamics are regulated by the activation of kinases via putative signaling pathways but with some unexpected findings as follows. First, the loss of germ cells from the seminiferous epithelium during androgen suppression was associated with a surge in myotubularin-related protein 2 (MTMR2, a lipid phosphatase, in which adult MTMR2−/− mice were recently shown to be azoospermic because of the loss of cell adhesion function between germ and Sertoli cells); kinases: phosphatidylinositol 3-kinase, c-Src, and C-terminal Src kinase; adaptors: α-actinin, vinculin, afadin, and p130 Crk-associated protein; and AJ-integral membrane proteins at the ectoplasmic specialization (ES, a testis-specific cell-cell actin-based AJ type) site: N-cadherin, β-catenin, integrin β1, and nectin 3. Second, MTMR2, instead of structurally interacting with phosphatidylinositol 3-kinase, a protein and lipid kinase, was shown to associate only with c-Src, a nonreceptor protein tyrosine kinase, as demonstrated by both coimmunoprecipitation and fluorescent microscopy at the site of apical ES, but none of the kinases, adaptors, and AJ-integral proteins that were examined. Collectively, these results suggest that the MTMR2/c-Src is an important phosphatase/kinase protein pair in AJ dynamics in the testis. Because c-Src is known to associate with the cadherin/catenin protein complex at the ES in the testis, we next sought to investigate any changes in the protein-protein interactions of this protein complex during androgen suppression-induced germ cell loss. Indeed, there was a loss of N-cadherin and β-catenin association, accompanied by a surge in Tyr phosphorylation of β-catenin, during germ cell loss from the epithelium. Third, and perhaps the most important of all, during natural recovery of the epithelium after removal of testosterone-estradiol implants when spermatids were reattaching to Sertoli cells, an increase in N-cadherin and β-catenin association was detected with a concomitant loss in the increased Tyr phosphorylation in β-catenin. In summary, these results illustrate that the cadherin/catenin is a crucial cell adhesion complex that regulates AJ dynamics in the testis, and its functionality is likely modulated by the MTMR2/c-Src protein complex.
Peroxisome Proliferator-Activated Receptor δ Suppresses 11β-Hydroxysteroid Dehydrogenase Type 2 Gene Expression in Human Placental Trophoblast Cells
Authors: Julan Laura , Guan Haiyan , van Beek Jonathan P. , Yang Kaiping
Published: February 2005

Accumulating evidence suggests that the human placental enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) plays a key role in fetal development by controlling fetal exposure to maternal glucocorticoids. Recently, the nuclear peroxisome proliferator-activated receptor δ (PPARδ) has been found to be the most abundantly expressed PPAR subtype in the human placenta, but its function in this organ is unknown. Given that PPARδ-null mice exhibited placental defects and consequent intrauterine growth restriction, the present study was undertaken to examine the hypothesis that PPARδ regulates human placental function in part by targeting 11β-HSD2. Using cultured human trophoblast cells as a model system, we demonstrated that 1) the putative PPARδ agonist carbaprostacyclin (cPGI2) reduced 11β-HSD2 activity as well as 11β-HSD2 expression at both protein and mRNA levels; 2) GW610742 (a selective PPARδ agonist) mimicked the effect of cPGI2, whereas indomethacin (a known ligand for PPARα and PPARγ) had no effect; 3) the cPGI2-induced down-regulation of 11β-HSD2 mRNA did not require de novo protein synthesis; 4) cPGI2 suppressed HSD11B2 promoter activity, but did not alter the half-life of 11β-HSD2 mRNA; and 5) the inhibitory effect of cPGI2 on HSD11B2 promoter activity was abrogated in trophoblast cells cotransfected with a dominant negative PPARδ mutant. Taken together, these findings suggest that activation of PPARδ down-regulates HSD11B2 gene expression in human trophoblast cells, and that this effect is mediated primarily at the transcriptional level. Thus, the present study reveals 11β-HSD2 as an additional target for PPARδ and identifies a molecular mechanism by which this nuclear receptor may regulate human placental function.
On the crystal structure of γ-AgMg4
Authors: Kudla Christian , Prots Yurii , Leineweber Andreas , Kreiner Guido
Published: February 2005

The title compound with the trivial name γ-AgMg4 is obtained by melting the elements in weld-sealed tantalum ampoules and subsequent annealing. The alloys were characterized by chemical, metallographic, thermal and X-ray powder analyses. γ-AgMg4 is formed by a peritectoid reaction at 472(2) °C from ɛ′-Ag17Mg54 and δ-(Mg). The exact composition corresponds to the formulas AgMg4.08 or Ag9Mg36.7 with 80.3(1) at-% Mg concentration. The title compound is a complex metallic alloy phase due to the large number of atoms and intrinsic structural disorder. γ-AgMg4 crystallizes hexagonal in the space group P63/m with a = 12.4852(8) Å and c = 14.4117(9) Å in a unique structure type without a perceptible homogeneity range. The crystal structure has been studied including disorder phenomena by means of Rietveld refinements of X-ray and neutron powder diffraction data and X-ray single crystal structure analyses. The crystal structure is a hitherto unknown I3 cluster phase, i.e., an intermetallic compound with building blocks of three vertex connected icosahedra as the fundamental structural units joined via a small number of connection types (here B- and L-type). Channels along [001] reveal distinct structural disorder described as a packing of approximately 1.9 icosahedra, 1.3 tricapped trigonal prisms and 0.4 Frank-Kasper Z15 polyhedra per unit cell. The findings support the usefulness of the I3 cluster concept as a construction kit concerning not only simple subunits but also more complex “patches” with inherent structural disorder.