bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of progression of multi-state chronic disease using the Markov model and prevalence pool concept
Authors: Shih Hui-Chuan , Chou Pesus , Liu Chi-Ming , Tung Tao-Hsin
Published: November 2007

Background

We propose a simple new method for estimating progression of a chronic disease with multi-state properties by unifying the prevalence pool concept with the Markov process model.

Methods

Estimation of progression rates in the multi-state model is performed using the E-M algorithm. This approach is applied to data on Type 2 diabetes screening.

Results

Good convergence of estimations is demonstrated. In contrast to previous Markov models, the major advantage of our proposed method is that integrating the prevalence pool equation (that the numbers entering the prevalence pool is equal to the number leaving it) into the likelihood function not only simplifies the likelihood function but makes estimation of parameters stable.

Conclusion

This approach may be useful in quantifying the progression of a variety of chronic diseases.
The herpes simplex virus UL20 protein functions in glycoprotein K (gK) intracellular transport and virus-induced cell fusion are independent of UL20 functions in cytoplasmic virion envelopment
Authors: Melancon Jeffrey M , Fulmer Preston A , Kousoulas Konstantin G
Published: November 2007

The HSV-1 UL20 protein (UL20p) and glycoprotein K (gK) are both important determinants of cytoplasmic virion morphogenesis and virus-induced cell fusion. In this manuscript, we examined the effect of UL20 mutations on the coordinate transport and Trans Golgi Network (TGN) localization of UL20p and gK, virus-induced cell fusion and infectious virus production. Deletion of 18 amino acids from the UL20p carboxyl terminus (UL20 mutant 204t) inhibited intracellular transport and cell-surface expression of both gK and UL20, resulting in accumulation of UL20p and gK in the endoplasmic reticulum (ER) in agreement with the inability of 204t to complement UL20-null virus replication and virus-induced cell fusion. In contrast, less severe carboxyl terminal deletions of either 11 or six amino acids (UL20 mutants 211t and 216t, respectively) allowed efficient UL20p and gK intracellular transport, cell-surface expression and TGN colocalization. However, while both 211t and 216t failed to complement for infectious virus production, 216t complemented for virus-induced cell fusion, but 211t did not. These results indicated that the carboxyl terminal six amino acids of UL20p were crucial for infectious virus production, but not involved in intracellular localization of UL20p/gK and concomitant virus-induced cell fusion. In the amino terminus of UL20, UL20p mutants were produced changing one or both of the Y38 and Y49 residues found within putative phosphorylation sites. UL20p tyrosine-modified mutants with both tyrosine residues changed enabled efficient intracellular transport and TGN localization of UL20p and gK, but failed to complement for either infectious virus production, or virus-induced cell fusion. These results show that UL20p functions in cytoplasmic envelopment are separable from UL20 functions in UL20p intracellular transport, cell surface expression and virus-induced cell fusion.
Platelet-derived exosomes from septic shock patients induce myocardial dysfunction
Authors: Azevedo Luciano Cesar Pontes , Janiszewski Mariano , Pontieri Vera , Pedro Marcelo de Almeida , Bassi Estevão , Tucci Paulo José Ferreira , Laurindo Francisco Rafael Martins
Published: November 2007

Introduction

Mechanisms underlying inotropic failure in septic shock are incompletely understood. We previously identified the presence of exosomes in the plasma of septic shock patients. These exosomes are released mainly by platelets, produce superoxide, and induce apoptosis in vascular cells by a redox-dependent pathway. We hypothesized that circulating platelet-derived exosomes could contribute to inotropic dysfunction of sepsis.

Methods

We collected blood samples from 55 patients with septic shock and 12 healthy volunteers for exosome separation. Exosomes from septic patients and healthy individuals were investigated concerning their myocardial depressant effect in isolated heart and papillary muscle preparations.

Results

Exosomes from the plasma of septic patients significantly decreased positive and negative derivatives of left ventricular pressure in isolated rabbit hearts or developed tension and its first positive derivative in papillary muscles. Exosomes from healthy individuals decreased these variables non-significantly. In hearts from rabbits previously exposed to endotoxin, septic exosomes decreased positive and negative derivatives of ventricular pressure. This negative inotropic effect was fully reversible upon withdrawal of exosomes. Nitric oxide (NO) production from exosomes derived from septic shock patients was demonstrated by fluorescence. Also, there was an increase in myocardial nitrate content after exposure to septic exosomes.

Conclusion

Circulating platelet-derived exosomes from septic patients induced myocardial dysfunction in isolated heart and papillary muscle preparations, a phenomenon enhanced by previous in vivo exposure to lipopolysaccharide. The generation of NO by septic exosomes and the increased myocardial nitrate content after incubation with exosomes from septic patients suggest an NO-dependent mechanism that may contribute to myocardial dysfunction of sepsis.
The global landscape of sequence diversity
Authors: Peregrín-Álvarez José Manuel , Parkinson John
Published: November 2007

Background

Systematic comparisons between genomic sequence datasets have revealed a wide spectrum of sequence specificity from sequences that are highly conserved to those that are specific to individual species. Due to the limited number of fully sequenced eukaryotic genomes, analyses of this spectrum have largely focused on prokaryotes. Combining existing genomic datasets with the partial genomes of 193 eukaryotes derived from collections of expressed sequence tags, we performed a quantitative analysis of the sequence specificity spectrum to provide a global view of the origins and extent of sequence diversity across the three domains of life.

Results

Comparisons with prokaryotic datasets reveal a greater genetic diversity within eukaryotes that may be related to differences in modes of genetic inheritance. Mapping this diversity within a phylogenetic framework revealed that the majority of sequences are either highly conserved or specific to the species or taxon from which they derive. Between these two extremes, several evolutionary landmarks consisting of large numbers of sequences conserved within specific taxonomic groups were identified. For example, 8% of sequences derived from metazoan species are specific and conserved within the metazoan lineage. Many of these sequences likely mediate metazoan specific functions, such as cell-cell communication and differentiation.

Conclusion

Through the use of partial genome datasets, this study provides a unique perspective of sequence conservation across the three domains of life. The provision of taxon restricted sequences should prove valuable for future computational and biochemical analyses aimed at understanding evolutionary and functional relationships.
Eosinophils induce DC maturation, regulating immunity
Authors: Lotfi Ramin , Lotze Michael Thomas
Published: November 2007

There are increased eosinophils in tumors, and they are generally associated with a good prognosis, whereas their presence in rejecting allografts is largely seen as a harbinger of poor outcome. The biologic role of eosinophils in their pathogenesis is more poorly understood than in allergy and asthma. Myeloid conventional dendritic cells (DCs) and conversely, plasmacytoid DCs are similarly associated with a good prognosis in cancer patients. We hypothesize that eosinophils, similar to NK cells, could mature DCs, and that could be responsible for regulating immunity in the setting of necrosis-associated chronic inflammation as occurs in cancer and transplant rejection. We have demonstrated that CpG DNA promotes eosinophil-induced DC maturation. As such, a greater linkage than had previously been considered between innate immune cells such as eosinophils and the adaptive immune response can be considered. Granulocytes were isolated from normal human whole blood by density gradient centrifugation followed by ammonium chloride-potassium lysis of the remaining red cells. Eosinophils were negatively separated using magnetic beads. Immature DCs were generated from CD-14 positively separated monocytes, which were cultured for 6 days with GM-CSF and IL-4. CpG ODN 2395 (CpG-C) as a pathogen-associated molecular pattern surrogate was used to induce eosinophil-based DC maturation. Transwells were used to assess cell–cell interaction between eosinophils and DCs. Eosinophil survival was assessed by flow cytometry; cells, which did not stain with Sytox-Orange, were considered viable. In the presence of CpG-C, eosinophils induced DC maturation. Similar results were obtained when eosinophils were pretreated with CpG for 4 h, washed, and cocultured afterwards with DCs. Eosinophil-induced maturation of DCs directly correlated with the eosinophil:DC ratio. Transwell studies showed that the direct cell–cell interaction between eosinophils and DCs enhances maturation. CpGs did not adversely affect eosinophil survival; thus, we could exclude the possibility that DC maturation was caused by sensing eosinophil cell death. While eosinophil-derived neurotoxin did not contribute to the described effect, DCs took up and internalized major basic protein (MBP), which was released from CpG-stimulated eosinophils, revealed by confocal imaging and flow cytometry. Thus, the DC maturational-inducing effect of eosinophils may be a result of released MBP from eosinophils. CpG-activated eosinophils mature conventional DCs. The role of viral or bacterial products or potentially, host-derived DNA as eosinophil activators with consequent DC maturation should be considered in more detail in the inflammatory settings in which eosinophils have been observed.
Commercial peptidoglycan preparations are contaminated with superantigen-like activity that stimulates IL-17 production
Authors: Li Hanfen , Nooh Mohammed M , Kotb Malak , Re Fabio
Published: November 2007

The immunomodulatory properties of peptidoglycan (PGN), a constituent of the bacterial cell wall, have been studied extensively but with contrasting results. Recent studies have demonstrated that the TLR2-mediated inflammatory responses elicited by Gram-positive PGN preparations are in fact a result of contaminating lipoproteins and lipoteichoic acid that can be removed only through sophisticated extraction procedures. Here, we report that commercial preparations of Staphylococcus aureus or Streptococcus pyogenes PGN are contaminated with bacterial superantigens (SAg). The T cell-derived cytokines IL-17A and IL-17F were induced by PGN preparations but not by TLR agonists or nucleotide-binding and oligomerization domain-like receptor agonists in human PBMC. IL-17 induction by PGN preparations was sensitive to protease digestion and required TCR signaling. Bacterial SAg could be detected by immunoblot in the PGN preparations, and purified recombinant SAg were powerful inducers of IL-17. Finally, the PGN preparations stimulated proliferation and expansion of T cells bearing specific TCR Vβ elements. Our results suggest that a large body of literature that relied on commercial PGN preparations to study inflammatory diseases, such as arthritis, where IL-17 also plays an important role, should be interpreted with caution and possibly revisited. Future studies aimed at characterizing the activities of PGN should use PGN preparations of proven purity.
Use of Patient-Reported Outcomes in Phase III Cancer Treatment Trials: Lessons Learned and Future Directions
Authors: Ganz Patricia A. , Gotay Carolyn C.
Published: November 2007

Purpose

This article examines the challenges, opportunities, and successes that have occurred in the incorporation of patient-reported outcomes (PROs) in phase III cancer clinical trials.

Methods

An informal survey of the leadership of US cooperative group PRO investigators identified diverse trials in which PROs had been measured. Exemplary trials were selected for lessons learned and for examination of successful strategies.

Results

We review four challenging trials in depth, illustrating some of the difficulties in integrating PROs within treatment trials, including issues related to missing data, lack of procedures for monitoring patients and ensuring collection of PRO data, and missed opportunities in publication of treatment and PRO outcomes together. Four examples of successful trials are highlighted.

Conclusion

As a result of this review, the authors make specific recommendations related to the use of PROs in phase III trials, focusing on issues related to design, choice of PRO instrument and frequency of administration, analysis, and publication strategies.
International Perspective on Health-Related Quality-of-Life Research in Cancer Clinical Trials: The European Organisation for Research and Treatment of Cancer Experience
Authors: Bottomley Andrew , Aaronson Neil K.
Published: November 2007

Over recent decades, health-related quality of life (HRQOL) research has been increasingly integrated into cancer clinical trials. The purpose of this review is to examine the overall approach taken towards clinical trial–based HRQOL investigations within the European Organisation for Research and Treatment of Cancer (EORTC). This article reports a literature review of clinical trial–based HRQOL investigations and provides selective examples of HRQOL studies in phase III clinical trials in various disease sites. The findings of this review highlight that, historically, assessing HRQOL was a challenge. However, as EORTC has become more experienced in the assessment of HRQOL and has developed a portfolio of appropriate tools, HRQOL has become a more accepted end point in large-scale trials. The trials reviewed in this article show that, in general, HRQOL data do provide information that can both inform clinicians about the effectiveness of the treatments and also serve as an invaluable source of information for patients to make informed decisions regarding the treatment choice.
Patient-Reported Outcomes Supporting Anticancer Product Approvals
Authors: Rock Edwin P. , Kennedy Dianne L. , Furness Melissa H. , Pierce William F. , Pazdur Richard , Burke Laurie B.
Published: November 2007

In 2006, the US Food and Drug Administration (FDA) published draft guidance to provide recommendations for development, validation, implementation, and interpretation of patient-reported outcome (PRO) measures that can support treatment benefit claims in product labeling. Here, we summarize and discuss FDA approvals of anticancer products in the context of the draft guidance. We identified anticancer product approvals having efficacy claim(s) based at least in part on a PRO. In addition, we collated limitations of PRO instruments commonly submitted for regulatory review over the period from October 1, 2004 to September 30, 2006. From 1995 onward, nine indications were approved for seven anticancer products based at least in part on a PRO. In eight of nine approvals, PRO data supplemented other evidence of clinical benefit. In seven approvals, the PRO measured a single symptom or functional domain that was directly attributable to the treatment benefit observed in the disease. The FDA's draft PRO guidance describes principles that have been used in anticancer product approvals for more than a decade. PRO end points typically support treatment benefit claims that refer to a patient's symptoms or ability to function. Single-item PROs may be acceptable. PRO data should be both internally consistent and aligned with other evidence of clinical benefit. The FDA encourages sponsors to consult with the FDA early in the process of PRO development.
Current Status of Patient-Reported Outcomes in Industry-Sponsored Oncology Clinical Trials and Product Labels
Authors: Gondek Kathleen , Sagnier Pierre-Philippe , Gilchrist Kim , Woolley J. Michael
Published: November 2007

Assessing patient-reported outcomes (PROs) in clinical trials is of interest to clinicians, patients, regulators, and industry. The use and impact of PROs is a growing area of methodologic research, particularly as they relate to tumor types, biomarkers, and various patient populations and cultures. Both the US Food and Drug Administration (FDA) and European Agency for the Evaluation of Medicinal Products in recent guidance have acknowledged the need to account for treatment-related impact on patient symptoms and/or health-related quality of life (HRQOL). Clinical research likely reflects the informative value of PROs. A search of www.clinicaltrials.gov , the FDA Web site, and product package inserts was conducted to assess the inclusion of symptom assessment and HRQOL within industry-sponsored clinical trials in cancer and approved cancer therapies and their respective product labels. Overall, there were 2,704 industry-sponsored oncology trials, of which 322 (12%) included a PRO measure. Of the 70 FDA new or revised labels, only six package inserts include PRO data. Symptoms were assessed uniformly across the phases of clinical trials, whereas HRQOL assessment increased in the later phases of clinical trials. Collecting PRO data can enhance our understanding of cancer burden and the impact of interventions on patients' lives.
Funding Patient-Reported Outcomes in Cancer Clinical Trials
Authors: Moinpour Carol M. , Denicoff Andrea M. , Bruner Deborah Watkins , Kornblith Alice B. , Land Stephanie R. , O'Mara Ann , Trimble Edward
Published: November 2007

We surveyed four cooperative groups to identify current funding sources for the collection and analysis effort associated with the inclusion of patient-reported outcome (PRO) data in cancer clinical trials. Survey questions included what proportion of staff effort was funded through the Cancer Therapy Evaluation Program (CTEP) and the Community Clinical Oncology Program (CCOP) grants. In addition, the groups were asked to what extent outside funding was solicited to cover an underfunded PRO effort (eg, the pharmaceutical industry, foundations, or National Institutes of Health grants). All four groups noted the challenge of making limited resources cover a number of trial responsibilities. PRO effort is usually bundled with effort required for all clinical trial data. There is variation in the use of the CTEP and CCOP grants to fund PRO research. The groups differed with respect to both the types and amount of outside funding used. This survey focused on funding sources for the conduct of PRO research in cooperative group trials; it did not assess the specific cost components associated with collecting and analyzing these data. In general, the costs for conducting PRO research have been bundled with other study costs because in most cases, the PRO has been considered an integral component of the trial. However, these data also suggest that PRO research has required the use of outside funding sources in the four surveyed cooperative groups and that PRO economic issues require attention if we are to continue the inclusion of these outcomes in cancer clinical trials.
Standardizing Patient-Reported Outcomes Assessment in Cancer Clinical Trials: A Patient-Reported Outcomes Measurement Information System Initiative
Authors: Garcia Sofia F. , Cella David , Clauser Steven B. , Flynn Kathryn E. , Lad Thomas , Lai Jin-Shei , Reeve Bryce B. , Wilder Smith Ashley , Stone Arthur A. , Weinfurt Kevin
Published: November 2007

Patient-reported outcomes (PROs), such as symptom scales or more broad-based health-related quality-of-life measures, play an important role in oncology clinical trials. They frequently are used to help evaluate cancer treatments, as well as for supportive and palliative oncology care. To be most beneficial, these PROs must be relevant to patients and clinicians, valid, and easily understood and interpreted. The Patient-Reported Outcomes Measurement Information System (PROMIS) Network, part of the National Institutes of Health Roadmap Initiative, aims to improve appreciably how PROs are selected and assessed in clinical research, including clinical trials. PROMIS is establishing a publicly available resource of standardized, accurate, and efficient PRO measures of major self-reported health domains (eg, pain, fatigue, emotional distress, physical function, social function) that are relevant across chronic illnesses including cancer. PROMIS is also developing measures of self-reported health domains specifically targeted to cancer, such as sleep/wake function, sexual function, cognitive function, and the psychosocial impacts of the illness experience (ie, stress response and coping; shifts in self-concept, social interactions, and spirituality). We outline the qualitative and quantitative methods by which PROMIS measures are being developed and adapted for use in clinical oncology research. At the core of this activity is the formation and application of item banks using item response theory modeling. We also present our work in the fatigue domain, including a short-form measure, as a sample of PROMIS methodology and work to date. Plans for future validation and application of PROMIS measures are discussed.
Patient-Reported Outcomes Assessment in Cancer Trials: Taking Stock, Moving Forward
Authors: Lipscomb Joseph , Reeve Bryce B. , Clauser Steven B. , Abrams Jeffrey S. , Watkins Bruner Deborah , Burke Laurie B. , Denicoff Andrea M. , Ganz Patricia A. , Gondek Kathleen , Minasian Lori M. , O'Mara Ann M. , Revicki Dennis A. , Rock Edwin P. , Rowland Julia H. , Sgambati Maria , Trimble Edward L.
Published: November 2007

To evaluate and improve the use of cancer trial end points that reflect the patient's own perspective, the National Cancer Institute organized an international conference, Patient-Reported Outcomes Assessment in Cancer Trials (PROACT), in 2006. The 13 preceding articles in this special issue of the Journal were commissioned in preparation for or in response to the PROACT conference, which was cosponsored by the American Cancer Society. Drawing from these articles and also commentary from the conference itself, this concluding report takes stock of what has been learned to date about the successes and challenges in patient-reported outcome (PRO) assessment in phase III, phase II, and symptom management trials in cancer and identifies ways to improve the scientific soundness, feasibility, and policy relevance of PROs in trials. Building on this synthesis of lessons learned, this article discusses specific administrative policies and management procedures to improve PRO data collection, analysis, and dissemination of findings; opportunities afforded by recent methodologic and technologic advances in PRO data collection and analysis to enhance the scientific soundness and cost efficiency of PRO use in trials; and the importance of better understanding the usefulness of PRO data to the full spectrum of cancer decision makers, including patients and families, health providers, public and private payers, regulatory agencies, and standards-setting organizations.
Patient-Reported Outcomes and the Evolution of Adverse Event Reporting in Oncology
Authors: Trotti Andy , Colevas A. Dimitrios , Setser Ann , Basch Ethan
Published: November 2007

Adverse event (AE) reporting in oncology has evolved from informal descriptions to a highly systematized process. The Common Terminology Criteria for Adverse Events (CTCAE) is the predominant system for describing the severity of AEs commonly encountered in oncology clinical trials. CTCAE clinical descriptors have been developed empirically during more than 30 years of use. The method of data collection is clinician based. Limitations of the CTC system include potential for incomplete reporting and limited guidance on data analysis and presentation methods. The Medical Dictionary for Regulatory Activities (MedDRA) is a comprehensive medical terminology system used for regulatory reporting and drug labeling. MedDRA does not provide for severity ranking of AEs. CTC-based data presentations are the primary method of AE data reporting used in scientific journals and oncology meetings. Patient-reported outcome instruments (PROs) cover the subjective domain of AEs. Exploratory work suggests PROs can be used with a high degree of patient engagement and compliance. Additional studies are needed to determine how PROs can be used to complement current AE reporting systems. Potential models for integrating PROs into AE reporting are described in this review. AE reporting methods will continue to evolve in response to changing therapies and growing interest in measuring the impact of cancer treatment on health status. Although integration of PROs into AE reporting may ultimately improve the comprehensiveness and quality of collected data, it may also increase the administrative burden and cost of conducting trials. Therefore, care must be used when developing health outcomes and safety data collection plans.
Health-Related Quality of Life and Symptom Management Research Sponsored by the National Cancer Institute
Authors: Minasian Lori M. , O'Mara Ann M. , Reeve Bryce B. , Denicoff Andrea M. , Kelaghan Joseph , Rowland Julia H. , Trimble Edward L.
Published: November 2007

For almost 30 years, the National Cancer Institute (NCI) has sponsored health-related quality-of-life (HRQOL) measures in cancer research as a means of including the patient's experience. The scope of NCI's research in symptom management and HRQOL is described with attention to its evolution over time and the next steps, through the Clinical Trials Working Group Recommendations.
Integrating Patient-Reported Outcomes Into Cancer Symptom Management Clinical Trials Supported by the National Cancer Institute–Sponsored Clinical Trials Networks
Authors: Sloan Jeff A. , Berk Lawrence , Roscoe Joseph , Fisch Michael J. , Shaw Edward G. , Wyatt Gwen , Morrow Gary R. , Dueck Amylou C.
Published: November 2007

Patient-reported outcomes (PROs) are often the primary end point in symptom management trials. The scientific field of PROs is evolving, as evidenced by the US Food and Drug Administration's February 2007 release of a draft guidance for using PROs in effectiveness claims for drug labeling. This article presents issues encountered during use of PROs in National Cancer Institute–sponsored symptom management trials. Selected trials are presented that exemplify the challenges often seen in symptom management trials, and solutions are described. The examples presented include defining the appropriate end point, selecting and validating assessments, and answering the research questions through statistical analysis and interpretation. Progress has been made in addressing some of the unique challenges of PRO-based symptom management research. Many challenges still remain, but a foundational body of work now exists for more consistent and rigorous application of PROs into symptom management trials. There remains a need for more research in several methodologic aspects of design, analysis, and interpretation of symptom management trials.
Pomc Knockout Mice Have Secondary Hyperaldosteronism Despite an Absence of Adrenocorticotropin
Authors: Linhart Kirsten-Berit , Majzoub Joseph A.
Published: November 2007

Aldosterone production is controlled by angiotensin II, potassium, and ACTH. Mice lacking Pomc and its pituitary product ACTH have been reported to have absent or low aldosterone levels, suggesting that ACTH is required for normal aldosterone production. However, this is at odds with the clinical finding that human aldosterone deficiency is not a component of secondary adrenal insufficiency. To resolve this, we measured plasma and urine electrolytes, together with plasma aldosterone and renin activity, in Pomc−/− mice. We found that these mice have secondary hyperaldosteronism (elevated aldosterone without suppression of renin activity), indicating that ACTH is not required for aldosterone production or release in vivo. Exogenous ACTH stimulates a further increase in aldosterone in Pomc−/− mice, whereas angiotensin II has no effect, and the combination of angiotensin II and ACTH is no more potent than ACTH alone. These data suggest that aldosterone production and release in vivo do not require the action of ACTH during development or postnatal life and that secondary hyperaldosteronism in Pomc−/− mice is a consequence of glucocorticoid deficiency.
Oral Supplementation with Physiological Doses of Leptin During Lactation in Rats Improves Insulin Sensitivity and Affects Food Preferences Later in Life
Authors: Sánchez Juana , Priego Teresa , Palou Mariona , Tobaruela Aixa , Palou Andreu , Picó Catalina
Published: November 2007

We have previously described that neonate rats supplemented with physiological doses of oral leptin during lactation become more protected against overweight in adulthood. The purpose of this study was to characterize further the long-term effects on glucose and leptin homeostasis and on food preferences. Neonate rats were supplemented during lactation with a daily oral dose of leptin or the vehicle. We followed body weight and food intake of animals until the age of 15 months, and measured glucose, insulin, and leptin levels under different feeding conditions: ad libitum feeding, 14-h fasting, and 3-h refeeding after fasting. An oral glucose tolerance test and a leptin resistance test were performed. Food preferences were also measured. Leptin-treated animals were found to have lower body weight in adulthood and to eat fewer calories than their controls. Plasma insulin levels were lower in leptin-treated animals than in their controls under the different feeding conditions, as was the increase in insulin levels after food intake. The homeostatic model assessment for insulin resistance index was significantly lower in leptin-treated animals, and the oral glucose tolerance test also indicated higher insulin sensitivity in leptin-treated animals. In addition, these animals displayed lower plasma leptin levels under the different feeding conditions and were also more responsive to exogenous leptin administration. Leptin-treated animals also showed a lower preference for fat-rich food than their controls. These observations indicate that animals supplemented with physiological doses of oral leptin during lactation were more protected against obesity and metabolic features of the metabolic syndrome.
Long-Term Effects of Central Leptin and Resistin on Body Weight, Insulin Resistance, and β-Cell Function and Mass by the Modulation of Hypothalamic Leptin and Insulin Signaling
Authors: Park Sunmin , Hong Sang Mee , Sung So Ra , Jung Hye Kyung
Published: November 2007

To determine the long-term effect of central leptin and resistin on energy homeostasis, peripheral insulin resistance, and β-cell function and mass, intracerebroventricular (ICV) infusion of leptin (3 ng/h), resistin (80 ng/h), leptin plus resistin, and cerebrospinal fluid (control) was conducted by means of an osmotic pump for 4 wk on normal rats and 90% pancreatectomized diabetic rats fed 40% fat-energy diets. Overall, the effects were greater in diabetic rats than normal rats. Leptin infusion, causing a significant reduction in food intake, decreased body weight and epididymal fat. However, resistin and leptin plus resistin reduced epididymal fat with decreased serum leptin levels in comparison with the control. Unlike serum leptin, only resistin infusion lowered serum resistin levels. Central leptin increased glucose infusion rates during euglycemic hyperinsulinemic clamp and suppressed hepatic glucose production in the hyperinsulinemic state in comparison with the control. However, central leptin did not affect glucose-stimulated insulin secretion and β-cell mass. Central resistin infusion also increased peripheral insulin sensitivity, but not as much as leptin. Unlike leptin, resistin significantly increased first-phase insulin secretion during hyperglycemic clamp and β-cell mass by augmenting β-cell proliferation. These metabolic changes were associated with hypothalamic leptin and insulin signaling. ICV infusion of leptin potentiated signal transducer and activator of transcription 3 phosphorylation and attenuated AMP kinase in the hypothalamus, but resistin had less potent effects than leptin. Leptin enhanced insulin signaling by potentiating IRS2→Akt pathways, whereas resistin activated Akt without augmenting insulin receptor substrate 2 phosphorylation. In conclusion, long-term ICV infusion of leptin and resistin independently improved energy and glucose homeostasis by modulating in different ways hypothalamic leptin and insulin signaling.
Activation of Thyroid Hormone Is Transcriptionally Regulated by Epidermal Growth Factor in Human Placenta-Derived JEG3 Cells
Authors: Canettieri Gianluca , Franchi Antonella , Guardia Michele Della , Morantte Ianessa , Santaguida Maria Giulia , Harney John W. , Larsen P. Reed , Centanni Marco
Published: November 2007

Human type II deiodinase is a master regulator of thyroid hormone activation in several tissues. In placenta, type II deiodinase mRNA levels and enzymatic activity are elevated only during the first trimester of pregnancy and then progressively decline. During this early stage, mitogens such as epidermal growth factor (EGF) have been shown to promote the proliferation of the trophoblast by acting through multiple mechanisms. Here we show that EGF modulates transcription of human type II deiodinase gene (Dio2) through distinct signaling pathways, leading to the assembly of a heterogeneous transcription factor complex. Gene expression and deiodination assays have shown that EGF promptly induces a short-lived Dio2 mRNA and enzymatic activity. The induction is mediated by ERK and p38 kinases, as demonstrated by selective inhibition or overexpression of different mitogen-activated kinases. Reporter assays of mutant constructs indicate that EGF-induced transcriptional activity on Dio2 promoter is mediated by the cAMP response element (CRE) and does not involve the activating protein 1 site. With functional and biochemical approaches, we have demonstrated that the EGF stimulation culminates with the assembly and recruitment over the Dio2 CRE of a composite complex, which consists of c-Jun, c-Fos, and CRE-binding protein. These results further support the hypothesis that placental iodothyronine metabolism is critical during early pregnancy.
Proteolytic Cleavage of Human Chromogranin A Containing Naturally Occurring Catestatin Variants: Differential Processing at Catestatin Region by Plasmin
Authors: Biswas Nilima , Vaingankar Sucheta M. , Mahata Manjula , Das Madhusudan , Gayen Jiaur R. , Taupenot Laurent , Torpey Justin W. , O’Connor Daniel T. , Mahata Sushil K.
Published: November 2007

The plasma level of chromogranin A (CgA) is elevated in genetic hypertension. Conversely, the plasma level of the CgA peptide catestatin is diminished in individuals with established hypertension and those with a genetic risk of this disease. Resequencing of the human CHGA gene identified three naturally occurring variants of catestatin (Gly364Ser, Pro370Leu, and Arg374Gln) that exhibit different potencies in inhibiting catecholamine secretion. Here, we have examined whether there is any differential processing of the three CHGA variants to catestatin by the endoproteolytic enzyme plasmin. Plasmin digestion of the purified CgA proteins generated a stable biologically active 14-amino acid peptide (human CgA360–373) from the wild-type, Gly364Ser, and Arg374Gln proteins despite the disruption of the dibasic site (Arg373Arg374) in the Arg374Gln variant. Unexpectedly, the action of plasmin in generating the catestatin peptide from the Pro370Leu protein was less efficient. The efficiency of cleavage at the dibasic Arg373↓Arg374 site in synthetic human CgA360–380 was 3- to 4-fold less in Pro370Leu CgA, compared with the wild type. Circular dichroism of the synthetic CgA352–372 suggested a difference in the amount of α-helix and β-sheet between the wild-type and Pro370Leu CgA peptides. Because the Pro370 residue is in the P4 position, the local secondary structure in the vicinity of the cleavage site may enforce the specificity or accessibility to plasmin. The less efficient proteolytic processing of the Pro370Leu protein by plasmin, coupled with the strong association of this variant with ethnicity, suggests that the Pro370Leu CHGA gene variant may contribute to the differential prevalence of cardiovascular disease across ethnic groups.
Progesterone Receptor Membrane Component-1 (PGRMC1) Is the Mediator of Progesterone’s Antiapoptotic Action in Spontaneously Immortalized Granulosa Cells As Revealed by PGRMC1 Small Interfering Ribonucleic Acid Treatment and Functional Analysis of PGRMC1 Mutations
Authors: Peluso John J. , Romak Jonathan , Liu Xiufang
Published: November 2007

Progesterone (P4) receptor membrane component-1 (PGRMC1) and its binding partner, plasminogen activator inhibitor 1 RNA binding protein (PAIRBP1) are thought to form a complex that functions as membrane receptor for P4. The present investigations confirm PGRMC1’s role in this membrane receptor complex by demonstrating that depleting PGMRC1 with PGRMC1 small interfering RNA results in a 60% decline in [3H]P4 binding and the loss of P4’s antiapoptotic action. Studies conducted on partially purified GFP-PGRMC1 fusion protein indicate that [3H]P4 specifically binds to PGRMC1 at a single site with an apparent Kd of about 35 nm. In addition, experiments using various deletion mutations reveal that the entire PGRMC1 molecule is required for maximal [3H]P4 binding and P4 responsiveness. Analysis of the binding data also suggests that the P4 binding site is within a segment of PGRMC1 that is composed of the transmembrane domain and the initial segment of the C terminus. Interestingly, PAIRBP1 appears to bind to the C terminus between amino acids 70–130, which is distal to the putative P4 binding site. Taken together, these data provide compelling evidence that PGRMC1 is the P4 binding protein that mediates P4’s antiapoptotic action. Moreover, the deletion mutation studies indicate that each domain of PGRMC1 plays an essential role in modulating PGRMC1’s capacity to both bind and respond to P4. Additional studies are required to more precisely delineate the role of each PGRMC1 domain in transducing P4’s antiapoptotic action.
Life-Long Caloric Restriction Reveals Biphasic and Dimorphic Effects on Bone Metabolism in Rodents
Authors: Tatsumi Sawako , Ito Masako , Asaba Yutaro , Tsutsumi Kumi , Ikeda Kyoji
Published: November 2007

Caloric restriction (CR) extends the lifespan of various organisms and slows the onset of age-related disorders; however, little is known about the long-term effects of CR per se on bone. In the present study, we have examined the effects of life-long CR vs. ad libitum (AD) feeding, mainly on the trabecular bone of proximal tibiae in male C57BL/6 mice and F344 rats. Micro-computed tomography scanning of tibiae revealed that CR for 3–9 months caused a substantial decrease in three-dimensional bone volume with structural derangements. Bone histomorphometry revealed the reduced bone mass was due mainly to suppression of bone formation. In db/db mice with defective leptin receptor, CR was unable to decrease bone mass and suppress bone formation. The effect of CR on bone mass was inhibited by administration of a β-adrenergic blocker, propranolol. Thus, CR may regulate bone formation through leptin signaling and elevated sympathetic nervous tone. Interestingly, the difference in bone volume between the CR and AD groups disappeared after 1 yr of age, and mice and rats on an additional extension of CR to natural death maintained higher bone mass than the AD groups, with reduced bone turnover, suggesting that CR slows skeletal aging by regulating the rate of bone turnover. This is the first report, to our knowledge, that has examined the effects of lifelong CR on bone metabolism and trabecular microstructure and documents its contrasting effects during maturation vs. the postmaturational, involutional period.
Therapeutic Potential of Atrial Natriuretic Peptide Administration on Peripheral Arterial Diseases
Authors: Park Kwijun , Itoh Hiroshi , Yamahara Kenichi , Sone Masakatsu , Miyashita Kazutoshi , Oyamada Naofumi , Sawada Naoya , Taura Daisuke , Inuzuka Megumi , Sonoyama Takuhiro , Tsujimoto Hirokazu , Fukunaga Yasutomo , Tamura Naohisa , Nakao Kazuwa
Published: November 2007

Peripheral arterial diseases are caused by arterial sclerosis and impaired collateral vessel formation, which are exacerbated by diabetes, often leading to leg amputation. We have reported that an activation of the natriuretic peptides/cGMP/cGMP-dependent protein kinase pathway accelerated vascular regeneration and blood flow recovery in murine legs, for which ischemia had been induced by a femoral arterial ligation as a model for peripheral arterial diseases. In this study, ip injection of carperitide, a human recombinant atrial natriuretic peptide, accelerated blood flow recovery with increasing capillary density in ischemic legs not only in nondiabetic mice but also in mice kept upon streptozotocin-induced hyperglycemia for 16 wk, which significantly impaired the blood flow recovery compared with nondiabetic mice. Based on these findings, we tried to apply the administration of carperitide to the treatment of peripheral arterial diseases. The study group comprised a continuous series of 13 patients with peripheral arterial diseases (Fontaine’s classification I, one; II, five; III, two; and IV, five), for whom conventional therapies had not accomplished appreciable results. Carperitide was administrated continuously and intravenously for 2 wk to Fontaine’s class I–III patients and for 4 weeks to class IV patients. The dose was gradually increased to the maximum, with the patient’s systolic blood pressure being kept above 100 mm Hg. Carperitide administration improved the ankle-brachial pressure index, intermittent claudication, rest pain, and ulcers. In conclusion, this study showed a therapeutic potential of carperitide to treat peripheral arterial diseases refractory to conventional therapies.
Expression of the Hepatic Specific V1 Messenger Ribonucleic Acid of the Human Growth Hormone Receptor Gene Is Regulated by Hepatic Nuclear Factor (HNF)-4α2 and HNF-4α8
Authors: Cynthia Cynthia , Rhani Zakaria , Zheng Hong
Published: November 2007

Human (h) GH plays an essential role in growth and metabolism, and its effectiveness is modulated by the availability of its specific receptor [hGH receptor (hGHR)] on target cells. The hGHR gene has a complex 5′-regulatory region containing multiple first exons. Seven are clustered within two small regions: V2,V3,V9 (module A) and V1,V4,V7,V8 (module B). Module A-derived mRNAs are ubiquitously expressed whereas those from module B are only found in postnatal liver, suggesting developmental- and liver-specific regulation of module B hGHR gene expression. To characterize the elements regulating module B activity, we studied a 1.8-kb promoter of the highest expressing exon in liver, V1. This promoter was repressed in transfection assays; however, either 5′- or 3′-deletions relieved this, suggesting the presence of multiple negative regulatory elements. Six putative hepatic nuclear factor 4 (HNF-4) response elements were identified. We determined that HNF-4α is developmentally regulated in the human liver: HNF-4α2 and HNF-4α8 are expressed in fetal hepatocytes but only HNF-4α2 is expressed in postnatal liver. Transient transfection assays demonstrated that HNF-4α2 and HNF-4α8 have a similar dual effect on V1 transcription: activation via site 1 in the proximal promoter and repression through site 6, approximately 1.7 kb upstream. EMSA/electrophoretic mobility supershift assays and chromatin immunoprecipitation analyses confirmed these two sites are bound by HNF-4α. Based on these data, we speculate there are multiple regions working together to repress the expression of V1 hGHR transcripts in tissues other than the normal postnatal liver, and that HNF-4α is a good candidate for regulating V1 hGHR expression in the human hepatocyte.
Argonaute 1 regulates the fate of germline stem cells inDrosophila
Authors: Yang Lele , Chen Dongsheng , Duan Ranhui , Xia Laixin , Wang Jun , Qurashi Abrar , Jin Peng , Chen Dahua
Published: November 2007

The Argonaute-family proteins play crucial roles in small-RNA-mediated gene regulation. In Drosophila, previous studies have demonstrated that Piwi, one member of the PIWI subfamily of Argonaute proteins, plays an essential role in regulating the fate of germline stem cells (GSCs). However,whether other Argonaute proteins also play similar roles remains elusive. Here, we show that overexpression of Argonaute 1 (AGO1) protein, another subfamily (AGO) of the Argonaute proteins, leads to GSC overproliferation,whereas loss of Ago1 results in the loss of GSCs. Combined with germline clonal analyses of Ago1, these findings strongly support the argument that Ago1 plays an essential and intrinsic role in the maintenance of GSCs. In contrast to previous observations of Piwi function in the maintenance of GSCs, we show that AGO1 is not required for bag of marbles (bam) silencing and probably acts downstream or parallel of bam in the regulation of GSC fate. Given that AGO1 serves as a key component of the miRNA pathway, we propose that an AGO1-dependent miRNA pathway probably plays an instructive role in repressing GSC/cystoblast differentiation.
Monitoring an Information Source Under a Politeness Constraint
Authors: Eckstein Jonathan , Gal Avigdor , Reiner Sarit
Published: November 2007

We describe scheduling algorithms for monitoring a single information source whose contents change at times modeled by a nonhomogeneous Poisson process. In a given time period of length T, we enforce a server-side politeness constraint that we may only probe the source at most n times. This constraint, along with an optional constraint that no two probes may be spaced less than δ time units apart, is intended to prevent the monitor from being classified as a nuisance to be “locked out” of the information source. To develop our algorithms, we use a portion of the cost model developed in our earlier work. Our first algorithm assumes a discrete set of N > n possible update times, and uses dynamic programming to identify a provably optimal subset of n of these times at which to probe the server. Our second algorithm is a simple direct search for locally improving any continuous-time schedule with respect to the same cost model. In particular, this improvement procedure may be applied to the schedule obtained from our first algorithm. We evaluate our algorithms using real-world data feeds.
The Integrated Production and Transportation Scheduling Problem for a Product with a Short Lifespan
Authors: Geismar H. Neil , Laporte Gilbert , Lei Lei , Sriskandarajah Chelliah
Published: November 2007

The integrated production and transportation scheduling problem (PTSP) with capacity constraints is common in many industries. An optimal solution to PTSP requires one to simultaneously solve the production scheduling and the transportation routing problems, which requires excessive computational time, even for relatively small problems. In this study, we consider a variation of PTSP that involves a short shelf life product; hence, there is no inventory of the product in process. Once a lot of the product is produced, it must be transported with nonnegligible transportation time directly to various customer sites within its limited lifespan. The objective is to determine the minimum time required to complete producing and delivering the product to meet the demand of a given set of customers over a wide geographic region. This problem is NP-hard in the strong sense. We analyze the properties of this problem, develop lower bounds on the optimal solution, and propose a two-phase heuristic based on the analysis. The first phase uses either a genetic or a memetic algorithm to select a locally optimal permutation of the given set of customers; the second phase partitions the customer sequence and then uses the Gilmore-Gomory algorithm to order the subsequences of customers to form the integrated schedule. Empirical observations on the performance of this heuristic are reported.