bluuebunny/crossref_metadata_2025 huggingface dataset:
Prior hypoglycemia enhances glucose responsiveness in some ventromedial hypothalamic glucosensing neurons
Authors: Kang Ling , Sanders Nicole M. , Dunn-Meynell Ambrose A. , Gaspers Larry D. , Routh Vanessa H. , Thomas Andrew P. , Levin Barry E.
Published: December 2007

Antecedent insulin-induced hypoglycemia (IIH) reduces adrenomedullary responses (AMR) to subsequent bouts of hypoglycemia. The ventromedial hypothalamus [VMH: arcuate (ARC) + ventromedial nuclei] contains glucosensing neurons, which are thought to be mediators of these AMR. Since type 1 diabetes mellitus often begins in childhood, we used juvenile (4- to 5-wk-old) rats to demonstrate that a single bout of IIH (5 U/kg sc) reduced plasma glucose by 24% and peak epinephrine by 59% 1 day later. This dampened AMR was associated with 46% higher mRNA for VMH glucokinase, a key mediator of neuronal glucosensing. Compared with neurons from saline-injected rats, ventromedial nucleus glucose-excited neurons from insulin-injected rats demonstrated a leftward shift in their glucose responsiveness (EC50= 0.45 and 0.10 mmol/l for saline and insulin, respectively, P = 0.05) and a 31% higher maximal activation by glucose ( P = 0.05), although this maximum occurred at a higher glucose concentration (saline, 0.7 vs. insulin, 1.5 mmol/l). Although EC50values did not differ, ARC glucose-excited neurons had 19% higher maximal activation, which occurred at a lower glucose concentration in insulin- than saline-injected rats (saline, 2.5 vs. insulin, 1.5 mmol/l). In addition, ARC glucose-inhibited neurons from insulin-injected rats were maximally inhibited at a fivefold lower glucose concentration (saline, 2.5 vs. insulin, 0.5 mmol/l), although this inhibition declined at >0.5 mmol/l glucose. These data suggest that the increased VMH glucokinase after IIH may contribute to the increased responsiveness of VMH glucosensing neurons to glucose and the associated blunting of the AMR.
Mitochondrial Resequencing Arrays Detect Tumor-Specific Mutations in Salivary Rinses of Patients with Head and Neck Cancer
Authors: Mithani Suhail K. , Smith Ian M. , Zhou Shaoyu , Gray Andrew , Koch Wayne M. , Maitra Anirban , Califano Joseph A.
Published: December 2007

Purpose: Alterations of the mitochondrial genome have been identified in multiple solid tumors and in many head and neck squamous cell carcinomas (HNSCC). Identification of mitochondrial mutations in the salivary rinses of patients with HNSCC has potential application in disease detection. In this study, we used the MitoChip v2.0 mitochondrial genome resequencing array to detect minor populations of mitochondrial DNA in salivary rinses of patients with HNSCC.

Experimental Design: Salivary rinses from 13 patients with HNSCC, whose tumors carried mitochondrial mutations, were collected before surgical resection. DNA isolated from salivary rinses and serial dilutions of DNA derived from HNSCC-derived cell lines with known mitochondrial mutations were sequenced using the MitoChip, and analyzed using a quantitative algorithm which we developed to detect minor populations of mitochondrial DNA from MitoChip probe intensity data.

Results: We detected heteroplasmic populations of mitochondrial DNA up to a 1:200 dilution using MitoChip v2.0 and our analysis algorithm. A logarithmic relationship between the magnitude of assay intensity and concentration of minor mitochondrial populations was shown. This technique was able to identify tumor-specific mitochondrial mutations in salivary rinses from 10 of 13 (76.9%) patients with head and neck cancer.

Conclusions: Minor populations of mitochondrial DNA and disease-specific mitochondrial mutations in salivary rinses of patients with HNSCC can be successfully identified using the MitoChip resequencing array and the algorithm which we have developed. This technique has potential application in the surveillance of patients after resection and may have applicability in the surveillance of body fluids in other tumor types.
Analysis of hMLH1 Missense Mutations in East Asian Patients with Suspected Hereditary Nonpolyposis Colorectal Cancer
Authors: Fan Yimei , Wang Wei , Zhu Ming , Zhou Jiji , Peng Jingyuan , Xu Lizhi , Hua Zichun , Gao Xiang , Wang Yaping
Published: December 2007

Purpose: Germ line mutations in the DNA mismatch repair gene hMLH1 are a frequent cause of hereditary nonpolyposis colorectal cancer and about one-third of these are missense mutations. Several missense mutations in hMLH1 have frequently been detected in East Asian patients with suspected hereditary nonpolyposis colorectal cancer, but their pathogenic role has not been extensively assessed. The aim of this study was to perform functional analyses of these variants and their association with gastrointestinal cancer in East Asians.

Experimental Design: Altogether, 10 hMLH1 variants were analyzed by yeast two-hybrid and coimmunoprecipitation assays.

Results: The carboxyl-terminal replacements Q542L, L549P, L574P, and P581L in hMLH1 resulted in complete loss of activity in both yeast two-hybrid and coimmunoprecipitation tests and thus might be considered as pathogenic. The amino-terminal variants S46I, G65D, G67R, and R217C did not affect complex formation with hPMS2 in coimmunoprecipitation, but partly or fully lost their activity in yeast two-hybrid assay, and we suggested that these variants might reduce the efficiency of the heterodimer to go into the nucleus and thus the mismatch repair function might be blocked or reduced. The V384D and the Q701K variant resulted in the interaction of hMLH1 with hPMS2 at reduced efficiency and might raise the gastrointestinal cancer risk of the mutation carriers.

Conclusions: This work availably evaluated the functional consequences of some missense mutations not previously determined in the hMLH1 gene and might be useful for the clinical diagnosis of hereditary gastrointestinal cancer, especially in East Asians.
BRCA1 mRNA Expression Levels Predict for Overall Survival in Ovarian Cancer after Chemotherapy
Authors: Quinn Jennifer E. , James Colin R. , Stewart Gail E. , Mulligan Jude M. , White Patricia , Chang Gary K.F. , Mullan Paul B. , Johnston Patrick G. , Wilson Richard H. , Harkin D. Paul
Published: December 2007

Purpose: We investigated whether BRCA1 mRNA expression levels may represent a biomarker of survival in sporadic epithelial ovarian cancer following chemotherapy treatment.

Experimental Design: The effect of loss of BRCA1 expression on chemotherapy response in ovarian cancer was measured in vitro using dose inhibition assays and Annexin V flow cytometry. Univariate and multivariate analyses were done to evaluate the relationship between BRCA1 mRNA expression levels and survival after chemotherapy treatment in 70 fresh frozen ovarian tumors.

Results: We show that inhibition of endogenous BRCA1 expression in ovarian cancer cell lines results in increased sensitivity to platinum therapy and decreased sensitivity to antimicrotubule agents. In addition, we show that patients with low/intermediate levels of BRCA1 mRNA have a significantly improved overall survival following treatment with platinum-based chemotherapy in comparison with patients with high levels of BRCA1 mRNA (57.2 versus 18.2 months; P = 0.0017; hazard ratio, 2.9). Furthermore, overall median survival for higher-BRCA1-expressing patients was found to increase following taxane-containing chemotherapy (23.0 versus 18.2 months; P = 0.12; hazard ratio, 0.53).

Conclusions: We provide evidence to support a role for BRCA1 mRNA expression as a predictive marker of survival in sporadic epithelial ovarian cancer.
Allogeneic MHC Gene Transfer Enhances an Effective Antitumor Immunity in the Early Period of Autologous Hematopoietic Stem Cell Transplantation
Authors: Kobayashi Akihiko , Hara Hidehiko , Ohashi Masaki , Nishimoto Takeshi , Yoshida Kimiko , Ohkohchi Nobuhiro , Yoshida Teruhiko , Aoki Kazunori
Published: December 2007

Purpose: In autologous hematopoietic stem cell transplantation (HSCT), lymphopenia-induced homeostatic proliferation of T cells is driven by the recognition of self-antigens, and there is an opportunity to skew the T-cell repertoire during the T-cell recovery by engaging tumor-associated antigens, leading to a break of tolerance against tumors. However, the homeostatic proliferation–driven antitumor responses seem to decline rapidly in association with tumor growth. We hypothesized that a tumor-specific immune response induced by an immune gene therapy could enhance and sustain homeostatic proliferation–induced antitumor immunity.

Experimental Design: The antitumor effect of allogeneic MHC (alloMHC) gene transfer was examined at the early phase of the immune reconstitution after syngeneic HSCT.

Results: Syngeneic HSCT showed significant tumor growth inhibition of syngeneic colon cancer cells within a period of 30 days; however, the tumor then resumed rapid growth and the survival of the mice was not prolonged. In contrast, when the alloMHC plasmid was intratumorally injected at the early phase after syngeneic HSCT, the established tumors were markedly regressed and the survival of recipient mice was prolonged without significant toxicities, whereas no survival advantage was recognized in recipient mice injected with a control plasmid. This tumor suppression was evident even in the other tumors that were not injected with the alloMHC plasmid. The antitumor response was characterized by the development of tumor-specific T cell– and natural killer cell–mediated cytotoxicities.

Conclusion: The results suggest the efficacy and safety of integrating intratumoral alloMHC gene transfer with an autologous HSCT for the treatment of solid cancers.
Differential Effects of Combined Ad5-Δ24RGD and Radiation Therapy in In vitro versus In vivo Models of Malignant Glioma
Authors: Lamfers Martine L.M. , Idema Sander , Bosscher Lisette , Heukelom Stan , Moeniralm Sharif , van der Meulen-Muileman Ida H. , Overmeer Renée M. , van der Valk Paul , van Beusechem Victor W. , Gerritsen Winald R. , Vandertop W. Peter , Dirven Clemens M.F.
Published: December 2007

Purpose: The integrin-targeted conditionally replicating adenovirus Ad5-Δ24RGD has been shown to possess strong oncolytic activity in experimental tumors and is currently being developed toward phase I clinical evaluation for ovarian cancer and malignant glioma. Previously, we reported that combination therapy of Ad5-Δ24RGD with irradiation led to synergistic antitumor activity in s.c. glioma xenografts. In the current study, the underlying mechanism of action to this synergy was studied and the effects of combined therapy were assessed in an orthotopic glioma model.

Experimental Design and Results: Sequencing studies in U-87 monolayers showed that delivery of irradiation before Ad5-Δ24RGD infection led to a greater oncolytic effect than simultaneous delivery or infection before irradiation. This effect was not due to enhanced virus production or release. Experiments using a luciferase-encoding vector revealed a small increase in transgene expression in irradiated cells. In tumor spheroids, combination therapy was more effective than Ad5-Δ24RGD or irradiation alone. Staining of spheroid sections showed improved penetration of virus to the core of irradiated spheroids. Mice bearing intracranial tumors received a combination of Ad5-Δ24RGD with 1 × 5 Gy total body irradiation or with 2 × 6 Gy whole brain irradiation. In contrast to the in vitro data and reported results in s.c. tumors, addition of radiotherapy did not significantly enhance the antitumor effect of Ad5-Δ24RGD.

Conclusions: Combined treatment with Ad5-Δ24RGD and irradiation shows enhanced antitumor activity in vitro and in s.c. tumors, but not in an orthotopic glioma model. These differential results underscore the significance of the selected tumor model in assessing the effects of combination therapies with oncolytic adenoviruses.
Testing for homogeneity of gametic disequilibrium across strata
Authors: Yin Xiaolin , Ma Wenqing , Tang Manlai , Guo Jianhua
Published: December 2007

Background

Assessing the non-random associations of alleles at different loci, or gametic disequilibrium, can provide clues about aspects of population histories and mating behavior and can be useful in locating disease genes. For gametic data which are available from several strata with different allele probabilities, it is necessary to verify that the strata are homogeneous in terms of gametic disequilibrium.

Results

Using the likelihood score theory generalized to nuisance parameters we derive a score test for homogeneity of gametic disequilibrium across several independent populations. Simulation results demonstrate that the empirical type I error rates of our score homogeneity test perform satisfactorily in the sense that they are close to the pre-chosen 0.05 nominal level. The associated power and sample size formulae are derived. We illustrate our test with a data set from a study of the cystic fibrosis transmembrane conductance regulator gene.

Conclusion

We propose a large-sample homogeneity test on gametic disequilibrium across several independent populations based on the likelihood score theory generalized to nuisance parameters. Our simulation results show that our test is more reliable than the traditional test based on the Fisher's test of homogeneity among correlation coefficients.
Denoising inferred functional association networks obtained by gene fusion analysis
Authors: Kamburov Atanas , Goldovsky Leon , Freilich Shiri , Kapazoglou Aliki , Kunin Victor , Enright Anton J , Tsaftaris Athanasios , Ouzounis Christos A
Published: December 2007

Background

Gene fusion detection – also known as the 'Rosetta Stone' method – involves the identification of fused composite genes in a set of reference genomes, which indicates potential interactions between its un-fused counterpart genes in query genomes. The precision of this method typically improves with an ever-increasing number of reference genomes.

Results

In order to explore the usefulness and scope of this approach for protein interaction prediction and generate a high-quality, non-redundant set of interacting pairs of proteins across a wide taxonomic range, we have exhaustively performed gene fusion analysis for 184 genomes using an efficient variant of a previously developed protocol. By analyzing interaction graphs and applying a threshold that limits the maximum number of possible interactions within the largest graph components, we show that we can reduce the number of implausible interactions due to the detection of promiscuous domains. With this generally applicable approach, we generate a robust set of over 2 million distinct and testable interactions encompassing 696,894 proteins in 184 species or strains, most of which have never been the subject of high-throughput experimental proteomics. We investigate the cumulative effect of increasing numbers of genomes on the fidelity and quantity of predictions, and show that, for large numbers of genomes, predictions do not become saturated but continue to grow linearly, for the majority of the species. We also examine the percentage of component (and composite) proteins with relation to the number of genes and further validate the functional categories that are highly represented in this robust set of detected genome-wide interactions.

Conclusion

We illustrate the phylogenetic and functional diversity of gene fusion events across genomes, and their usefulness for accurate prediction of protein interaction and function.
Rice transposable elements are characterized by various methylation environments in the genome
Authors: Takata Miwako , Kiyohara Akihiro , Takasu Atsuko , Kishima Yuji , Ohtsubo Hisako , Sano Yoshio
Published: December 2007

Background

Recent studies using high-throughput methods have revealed that transposable elements (TEs) are a comprehensive target for DNA methylation. However, the relationship between TEs and their genomic environment regarding methylation still remains unclear. The rice genome contains representatives of all known TE families with different characteristics of chromosomal distribution, structure, transposition, size, and copy number. Here we studied the DNA methylation state around 12 TEs in nine genomic DNAs from cultivated rice strains and their closely related wild strains.

Results

We employed a transposon display (TD) method to analyze the methylation environments in the genomes. The 12 TE families, consisting of four class I elements, seven class II elements, and one element of a different class, were differentially distributed in the rice chromosomes: some elements were concentrated in the centromeric or pericentromeric regions, but others were located in euchromatic regions. The TD analyses revealed that the TE families were embedded in flanking sequences with different methylation degrees. Each TE had flanking sequences with similar degrees of methylation among the nine rice strains. The class I elements tended to be present in highly methylated regions, while those of the class II elements showed widely varying degrees of methylation. In some TE families, the degrees of methylation were markedly lower than the average methylation state of the genome. In two families, dramatic changes of the methylation state occurred depending on the distance from the TE.

Conclusion

Our results demonstrate that the TE families in the rice genomes can be characterized by the methylation states of their surroundings. The copy number and degree of conservation of the TE family are not likely to be correlated with the degree of methylation. We discuss possible relationships between the methylation state of TEs and their surroundings. This is the first report demonstrating that TEs in the genome are associated with a particular methylation environment that is a feature of a given TE.
Bilateral cytomegalovirus (CMV) oophoritis mimicking widely metastatic carcinoma: a case report and review of the literature
Authors: Yu Jing , Solano Francis X , Seethala Raja R
Published: December 2007

Ovarian cytomegalovirus (CMV) infection is a rare finding reported in autopsy studies of immunocompromised patients. We report the first case of bilateral CMV oophoritis diagnosed in surgical resection specimens from a 63-year-old woman with metastatic brain lesions undergoing whole brain radiation and steroid treatment. The ovarian involvement of CMV infection was an incidental finding during the colectomy and bilateral salpingo-oophorectomy procedure for gastrointestinal bleeding and presumed ovarian metastases. In contrast to the prevailing dogma, a review of the literature found similar prevalence of pre-menopausal and post-menopausal cases. While age related vasculopathy was thought to be the prevailing mechanism for CMV oophoritis, the observation of an inflammation mediated microthrombosis in our case provides a plausible age independent mechanism suggesting that both restrictive and obstructive vascular changes can be involved in the pathogenesis of CMV oophoritis. To avoid misdiagnosis, both pathologists and clinicians should recognize ovarian involvement by CMV as a possibility in the immunocompromised patient.
Editorial—Causality, Unintended Consequences and Deducing Shared Causes
Authors: Shugan Steven M.
Published: December 2007

Despite warnings against inferring causality from observed correlations or statistical dependence, some articles do. Observed correlation is neither necessary nor sufficient to infer causality as defined by the term's everyday usage. For example, a deterministic causal process creates pseudorandom numbers; yet, we observe no correlation between the numbers. Child height correlates with spelling ability because age causes both. Moreover, order is problematic—we hear train whistles before observing trains, yet trains cause whistles.

Scientific methods specifically prohibit inferring causal theories from specific observations (i.e., effects) because, in part, many credible causes are perfectly consistent with available observations. Moreover, actions inferred from effects have more unintended consequences than actions based on sound deductive causal theories because causal theories predict multiple effects. However, an often overlooked but key feature of these theories is that we describe the cause with more variables than the effect. Consequently, inductive processes might appear deductive as the number of effects increases relative to the number of potential causes. For example, in real criminal trials, jurors judge whether sufficient evidence exists to infer guilt. In contrast, determining guilt in criminal mystery novels is deductive because the number of clues (i.e., effects) is large relative to the number of potential suspects (i.e., causes). We can make inferential tasks resemble deductive tasks by increasing the number of effects (i.e., variables) relative to the number of potential causes and seeking a shared cause for all observed effects. Moreover, under some conditions, the method of seeking shared causes might approach deductive reasoning when the number of causes is strictly limited. At least, the resulting number of possible causal theories is far less than the number generated from repeated observations of a single effect (i.e., variable).
Overlapping Variance Estimators for Simulation
Authors: Alexopoulos Christos , Argon Nilay Tanık , Goldsman David , Tokol Gamze , Wilson James R.
Published: December 2007

To estimate the variance parameter (i.e., the sum of covariances at all lags) for a steady-state simulation output process, we formulate certain statistics that are computed from overlapping batches separately and then averaged over all such batches. We form overlapping versions of the area and Cramér–von Mises estimators using the method of standardized time series. For these estimators, we establish (i) their limiting distributions as the sample size increases while the ratio of the sample size to the batch size remains fixed; and (ii) their mean-square convergence to the variance parameter as both the batch size and the ratio of the sample size to the batch size increase. Compared with their counterparts computed from nonoverlapping batches, the estimators computed from overlapping batches asymptotically achieve reduced variance while maintaining the same bias as the sample size increases; moreover, the new variance estimators usually achieve similar improvements compared with the conventional variance estimators based on nonoverlapping or overlapping batch means. In follow-up work, we present several analytical and Monte Carlo examples, and we formulate efficient procedures for computing the overlapping estimators with only order-of-sample-size effort.
Leadership and Decision-making in New York City and London
Authors: Savitch H. V.
Published: December 2007

In recent years the idea of decentralisation has attained a controversial status among those concerned with the future of our cities. To its advocates, decentralisation is seen as a tool by which citizens can forge a sense of community and make their cities liveable; to others, it is a ruse which detracts from real problems, or worse, threatens the cosmopolitanism of our great cities. The debate continues across continents and by now the arguments for and against decentralisation seem to have outrun the empirical findings on the many forms it can take. This paper explores the forms and ramifications of decentralisation as it relates to the exercise of leadership in seven decentralised areas of two cities; New York and London.

Of the seven decentralised areas or sub-systems used for this study four were in New York City and three in London. The New York operations, called ‘neighbourhood districts’, include identifiable areas in various parts of the city. These are Crown Heights and Bushwickin Brooklyn, Wakefield Edenwald in the Bronx, and Washington Heights in Manhattan. The New York projects were begun in 1972, at the discretion of the Mayor, and represent the core of an experiment in administrative decentralisation.
An Anti-Labour Caucus: The Case of the Northumberland Voters’ Association
Authors: Beith A. J.
Published: December 2007

W. P. Grant has drawn attention to the lack of empirical study of local parties in British local government. He also draws a distinction between ‘genuine’ local parties and ‘concealed Conservative’ parties, and concentrates his attention on the former. He defines ‘concealed Conservative parties’ as those which are not prepared to fight an electoral contest against a Conservative candidate, and includes under this heading ‘Citizen’ and ‘Progressive’ parties. The framework for analysis which his article develops is confined to the ‘genuine’ local parties on this definition, which, while convenient, is not as reliable as first appears. English and Scottish local government contain several examples of what might better be described as ‘anti-Labour caucuses’ in the form of groups or alliances which have been prepared to fight against Conservative candidates when these have opposed them. J. H. R. Robbins, in a brief account of the Doncaster Progressives, has pointed out the limitations of Grant’s definition where such groups face opposition from renegade or ward-backed Conservatives. There are several such groups which need to be separately categorised; surprisingly they have received even less academic study than the ‘genuine’ local parties, although they hold or have held power in many county boroughs, county councils and Scottish cities.
Medical Characteristics of Children Supervised by the Local Authority Social Services Department
Authors: Brennan Mary E.
Published: December 2007

Children in the Registrar General’s classes IV and V are more likely to contract many diseases than the general population. They have a high infant mortality rate and are more likely to suffer from neural tube defects. Prematurity is more frequent in this group and is associated with a high rate of neonatal illness and a high subsequent prevalence of physical and mental handicap and emotional maladjustment. The incidence of episodes of illness in these children is greater not only when they are toddlers, but also when they attend primary schools. The reasons for this are not simple, but amongst other things these children have a poorer diet which is partly related to a larger family size and partly to a low family income. In Nottingham, Kedward demonstrated very little difference between the social classes in the use of primary medical care services during an acute episode of illness, but Cartwright found marked differences in the use of preventive services, which may have an adverse effect on the health of children in classes IV and V. The culture of poverty is probably related to these findings.
Attapulgite as a Thixotropic Suspending Agent
Authors: Wolford John
Published: December 2007

Attapulgite is a hydrous magnesium aluminum silicate clay mineral with a unique structure made up of colloidal particles called spicules. Gellation takes place following dispersion when the spicules become attracted to each other, become entangled and form the matrix structure that thickens, entraps, and suspends solids. Proper dispersion and gelling is dependent on the amount of shear and length of time it is applied or the use of chemical means to facilitate dispersion. To achieve gellation chemically dispersed clay must come into contact with a chemical salt which causes spicules to associate with one another and the gel to instantly form. Attapulgite can also be used to structure organic systems with the proper use of a cationic surfactant. The basic advantages of attapulgite as a structuring agent are versatility, compatibility with a variety of liquid systems, functionality over a wide pH range, and resistance to attack by microorganisms. It is relatively economical and provides a thixotropic liquid system.
Vena cava superior syndrome: surgical treatment of the thrombosis of the superior vena cava after implantation of a hemodialysis catheter – a case report and review of the literature
Authors: Lénárd László , Szabados Sándor , Imre Jenő , Pintér Örs , Fazekas Attila , Tornai Zoltán , Déczy Katalin , Várady Edit , Papp Lajos
Published: December 2007

A nem malignus eredetű vena cava superior szindróma egyik, viszonylag ritka kiváltó oka a vena cava superior trombózisa. Az egyre gyakrabban használt centrális vénás katéterek, pacemaker-elektródák alkalmazásának egyik szövődménye lehet a centrális vénák trombózis, hegesedés okozta beszűkülése, elzáródása. Egy fiatal, urémiás, 2000-ben Tesio-dializálókatéter-beültetésben részesült nőbeteg katéterdiszfunkcióhoz társuló vena cava superior trombózisáról, illetve annak extracorporalis keringésvédelemben történő sebészi megoldásáról számolunk be. Az eset kapcsán vázoljuk a vena cava superior szindróma malignus, nem malignus és iatrogén kiváltó okait, továbbá a gyógyszeres, sebészi, katéteres és egyéb terápiás lehetőségeket.
The prevention of the hypertension related damage in type-2 diabetes: the first step of the ADVANCE trial
Authors: Nagy Viktor
Published: December 2007

Az ADVANCE- (Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation) tanulmány széles körben vizsgálta a vérnyomáscsökkentés és az intenzív vércukorcsökkentés hasznát 2-es típusú diabetes mellitusban. Átlagosan 4,3 év követési idő után az aktív kezelésre kijelöltek 73%-a, a kontrollkezelésre kijelöltek 74%-a tartotta meg a randomizációkor kapott kezelést. A placebokezelésre kijelölt betegekkel összehasonlítva, az aktív kezelés a vérnyomást 5,6/2,2 Hgmm-rel csökkentette. A major macrovascularis és microvascularis események relatív kockázata 9%-kal csökkent (aktív: 861 [15,5%] vs placebo 938 [16,8%]; esélyhányados 0,91, 95% CI 0,83–1,00,
p
= 0,04). A perindopril és indapamide fix kombinációja ezért meglehetősen jó hatással védheti ki a hipertónia szövődményeit 2-es típusú diabéteszes betegekben.
Concrete and Other Alternative Platform Designs
Authors: Fumes Olav
Published: December 2007

The paper is chiefly devoted to the design, construction, installation and maintenance of concrete platforms. A review is given over the fixed concrete gravity platforms installed or under construction in the North Sea and elsewhere. The principles of design and construction is discussed with emphasis on –current design requirements and practice–evaluation of environmental loads foundation stability and geotechnical aspects–construction, tow-out and instal-1ation–aspects of inspection and maintenance.

The potential of applying concrete platforms for a range of water depths and soil conditions is discussed. Alternative fixed and floating concrete platforms for deep water and concepts which will not need sheltered, deep water for construction are outlined to some extent.

The experience from construction and operation of concrete platforms until now is summarized and certain design problems are looked into.

The paper concludes that prestressed and reinforced concrete, when designed and constructed in compliance with current criteria, is a well suited, durable and practically maintenance-free material for platforms exposed to the environmental conditions of the North Sea.

As for alternative platform designs other than concrete and conventional jackets, a review is given of platforms presently proposed. However brief, the review covers compliant and articulated towers, vertically moored platforms and tripod towers for deep water and hostile environment.
Sandstone Reservoirs
Authors: Weimer Robert J. , Tillman R. W.
Published: December 2007

The origin and distribution of a sandstone reservoir for petroleum are controlled primarily by the processes by which the sand was deposited. Studies of modern environments of deposition and associated Holocene deposits provide a basis for understanding petroleum fields and predicting reservoir distribution and behavior.

The Rocky Mountain province of the United States contains structural and stratigraphic traps from which petroleum is produced from all types of sandstone reservoirs ranging in age from Cambrian to the Eocene. Three large typical stratigraphic traps, where reservoirs are of Cretaceous age, are described. The Cut Bank field, Montana produces from alluvial point bar sandstones; Patrick Draw field, Wyoming produces from marine shoreline sandstones; and, Hartzog Draw field, Wyoming produces from marine shelf sandstones.
Optimizing the Development Plan
Authors: Rowan Grenville
Published: December 2007

It is perhaps unfortunate that the word optimal is used so frequently in the industry with no indication of the sense in which it is to be understood. This can be particularly confusing in development programs when groups working on different parts of the program each consider their individual contributions to be in some way "optimal". The question that naturally arises is whether the overall plan is optimal.

From a restricted point of view the optimizing of a field development might be considered as a particular example of optimization theory, such as optimal control or mathematical programming. If, from the outset, an attempt is made to formulate it in such terms, as a well-defined problem for which solutions are readily available, it would both detract from our understanding of the problem and cast the solution in a misleading role.

Complex, real-world problems, such as field development, contain elements that are incapable of precise description and may even contain features that are contradictory. Such problems do not have the desirable properties and precise formulations that are necessary if the extensive literature on optimization is to be available for immediate application. In fact, for such problems, the literature is poorly provided with solutions. Therefore, it is necessary to examine the field development problem carefully to see how, and to what extent, quantitative solutions may be sought.

Clearly, we must address the problem of what is meant by "optimal" in the context of field development planning and show how it is related to the decision problems. Thus the relevance of objectives, criteria, constraints and information must be emphasised.

The type of decision dictates the information required and, therefore, to a great extent the type of model that may be used for evaluation.

Because field development planning Is essentially a dynamic problem, time is a prime factor. The prediction of behaviour, upon which decisions are based is a function of the state of knowledge of both the reservoir and the production mechanism and these in turn depend upon decisions made prior to the development decision and the time at which they were made.

In real development problems there will never be an adequate description of the system. Hence, all development decisions are decisions in the face of uncertainty. This may be recognized by the introduction of the concept of "fuzziness" which offers more realistic evaluation models.
Remote Connection of Pipelines and Pipeline Stabilization
Authors: Brown Robert Joseph
Published: December 2007

As oil and gas are found in deeper water and rougher areas, engineering innovation is beginning to play an important part in the production development. This lecture discusses the latest innovative techniques being applied for the connection of single and bundled pipelines to risers, manifolds and other pipelines. Because of the high cost of surface equipment and manned intervention, these new systems are involving remote, diverless techniques to execute the connection. The slides will demonstrate the latest in the state-of-the-art of protection of pipelines by plowing techniques. This will include a brief history of how plowing began and will show details of the first commercial post-trenching plow used by Esso Australia in the Bass Strait. The future conceptual developments of the plowing techniques will also be discussed. The methods by which the concepts are developed, engineered and simulated will be illustrated with a discussion of how the model is used to establish the problem areas, and contingency plans for their solution. This concept is derived from aerospace practice and is being applied to pipeline installation, connection and stabilization.
The Role of Numerical Simulation in Reservoir Management of a West Texas Carbonate Reservoir
Authors: Harpole Kenneth J. , Hearn Charles L.
Published: December 2007

An effective reservoir management program is designed to optimize reservoir performance by assuring maximum economic return and recovery over the life of the reservoir. Such a program requires a continuing process of engineering and geologic study. Numerical reservoir simulation models provide a powerful tool for analyzing the production history of a reservoir and for predicting future performance under a variety of possible operating methods. Experience has shown that an accurate reservoir description is essential to the success of any numerical simulation study and to the development of an effective reservoir management plan1,2.

The mechanics of conducting a numerical simulation of reservoir performance are essentially the same for either a carbonate or sandstone reservoir. The most important difference in modeling these two general reservoir types involves the conceptual approach required to describe the lateral and vertical continuity of flow units within the reservoir. The continuity and internal characteristics of sandstones are controlled primarily by the original depositional system and environment, with usually only minor post-depositional changes. In carbonates, the distribution of porosity and permeability and the continuity of reservoir-quality units can be determined either by the original depositional environment, by post-depositional diagenetic changes, or, most commonly, by a combination of these factors.

Carbonate reservoir rock types are formed in a variety of depositional settings and show great diversity in size and form, ranging from reefs covering one or two square kilometers to extensive carbonate banks covering thousands of square kilometers3. The common characteristic of carbonate reservoirs is the extreme heterogeneity of porosity types and permeability distribution which results from the complex interaction of the physical, biological, and chemical processes that form these rocks. In addition, carbonate rocks are particularly susceptible to post-depositional diagenetic changes. Some of the more important diagenetic processes which act to alter the original rock texture in carbonates are dolomitization, recrystallization, cementation, and leaching or solution.
Waterflood Design (Pattern, Rate, and Timing)
Authors: Singh Surendra P. , Kiel O. Gerald
Published: December 2007

Waterflooding is the oldest and by far the most important method used by the petroleum industry to increase recovery from both onshore and offshore reservoirs. Waterflood design is a complex problem that must ultimately be handled on an individual reservoir basis. This paper presents factors that should be considered in designing both onshore and offshore waterfloods.

The need for careful examination of the following factors is discussed: Reservoir geology and method of depositionPrimary production mechanisms and stage of depletionReservoir and fluid propertiesReservoir pressureWell spacing and possible waterflood patterns

After these factors are discussed, the effects that pattern selection, timing and injection/producing rates have on project economics are discussed. A special emphasis is placed on offshore waterflooding since it is now of significant concern.
Sand Control Design Criteria and Gravel Packing Concepts
Authors: Suman George O. , Snyder Robert E.
Published: December 2007

Inflow of formation sand with oil and gas is one of the oldest production problems, particularly in shallower, high porosity sands containing heavy crudes, but also in younger age sands deposited in coastal areas both onshore and offshore. Developments in viscous fluid use and full scale model studies have improved the efficiency of gravel packing greatly. However, the most effective methods available are careful attention to proper design and installation procedures.

This presentation defines sand control and discusses basic causes of sand inflow such as grain-to-grain stress loss, viscous fluid drag and water increase effects, and liner slot distortion by borehole instability effects. Methods of predicting sand problems by subsidence monitoring, core and log studies, rate sensitivity tests, and surface detection are noted. Basic design criteria including gravel and screen slot sizing, liner selection, fluid selection, perforation design and well preparation requirements are summarized.

The final discussion is an overview of recommended industry gravel packing procedures including objectives of inside casing and open hole gravel packs, perforation cleaning and prepacking concepts and precautions, applications of viscous and non-viscous fluids, and brief descriptions of reverse circulation, crossover and "one trip" tool use.
Production Logging
Authors: McKinley R. M.
Published: December 2007

Production logging denotes that area of well logging concerned with two general goals: (1) problem well diagnosis, and (2) reservoir surveillance. The purpose of logging is to track fluid movement within or behind pipe or to monitor the movement of reservoir fluid contacts. The logs have been, traditionally, tools of the workover or subsurface engineer and the reservoir engineer. However, with the increasing hazards of drilling, the logs are becoming of vital importance to the drilling engineer. In many areas of the world, a suite of production logs are obtained before a particular well is even perforated for production. This is especially important for wells drilled within or near producing fields. Successful completions through strata with unequal pressures are difficult.

Because of the increasing importance of production logs, a survey of the subject is appropriate. In this paper, we review how the various logging tools work, what they measure, and how these measurements are related to flow. By example logs, we wish to illustrate three important points. First, production logs should be run in suites of complementing devices. Seldom does one log alone give satisfactory answers to a particular problem. Second, the subtle features, rather than the obvious anomalies, of a particular log often contain the desired information. Finally, production logging evolution has only recently turned in a direction of attempting to deal with multiphase flow of gases and liquids at low rates. As a result, the technology in this area is still insufficient.
Evaluation Of Hydraulic Fracturing By Transient Pressure Analysis Methods
Authors: Cinco Heber
Published: December 2007

Production of either wells completed in low permeability reservoirs or damaged wells has been possible because of hydraulic fractaring. The estimation of both the geometric and flow characteristics of a fracture represent a useful information for the calibration of fracture design methods and permits fore casting well flow behavior.

Transient pressure well test analysis has been used with success to estimate well conditions and reservoirs parameters. Conventional methods of interpretation are based on radial flow theory. This is a limitation when applied to fractured wells because they exhibit other type of flow at different times in a test.

Several authors have presented different techniques to calculate both reservoir and fracture parameters. These methods include the linear flow graph (Δp vs t), the bilinear flow graph (Δp vs Lt), the semilog graph (Δp vs log t) and type curve matching. Among these techniques, the type curve method deserves special attention because it allows both the analysis of pressure data and the detection of different flow regimes.
Laboratory Evaluation of Stuck Pipe Spotting Fluid Effectiveness
Authors: Krol David Alan
Published: December 2007

Laboratory evaluation of the effectiveness of spotting fluids in freeing differentially stuck pipe has been conducted in a specially designed simulator at temperatures ranging from 21.1°C (70°F) to 121.1°C (250°F). Conclusions are made from the data presented which establish the mechanism by which spotting fluids free stuck pipe. These results bear on the application of spotting fluids in field operations.
Comparison of Calculated and Measured Responses of a Dual-Detector Epithermal Neutron Porosity Device
Authors: Ellis D. V. , Ullo J. , Sherman H.
Published: December 2007

The development of an epithermal neutron porosity device has been greatly aided by model calculations to supplement laboratory measurements of environmental effects. Accurate computational models of this device have been developed using discrete ordinates and Monte Carlo techniques. The two techniques are quite different but complementary in their applicability to the situation under study.

The ability of the models to predict individual detector counting rates is demonstrated for the case of the basic porosity response. The validity of the models is further established by comparison with laboratory measurements of the experimental tool response to formation porosity, formation matrix, borehole size, tool stand-off, and temperature.
Operation and Development of a Well-Control Calculator Module
Authors: Zamora Mario
Published: December 2007

A new firmware module has been developed for a popular series of handheld, programmable calculators. Use of the module can help to minimize the occurrence of kicks and blowouts, facilitate well-control training and certification, and assist well-planning activities.

The module can be used by all levels of drilling personnel in routine and critical situations. It is programmed to handle calculations for surface/subsea BOP stacks, land/offshore locations, gas/salt-water kicks and straight/directional wells. The engineering programmes can be run in standard oilfield or SI metric units.

The purpose of this paper is to describe both the operation and development of this module. Major emphasis is placed on the use of the module in well-control and drilling operations.
Drilling Fluids and Practices for Central North Sea Tertiary Shales
Authors: Minton R. C.
Published: December 2007

An analysis is presented of drilling fluid costs and a detailed time analysis breakdown of seventy wells drilled over a period of 512 years, off the four platforms in British Petroleum's Forties Field. These wells, up to 67° average drift angle, have been drilled with a potassium cloride water based drilling fluid. The effect of changes in casing setting depth over this period is analysed and drilling practices are discussed.
Offshore Gas Conservation Utilising A Turbo-Expander Based Refrigeration Extraction Cycle
Authors: Ross I. , Robinson T.
Published: December 2007

Gas associated with the crude produced from Occidental's Piper field is conserved by drying it and condensing out the heavier components. This renders the gas with water and hydrocarbon dew points acceptable for transfer to St. Fergus via Total's Frigg field pipeline. A process which includes a turbo expander/compressor is used to extract the condensate which is spiked into the crude pipeline for eventual recovery as liquid product and fuel gas at Flotta. The turbo expander can extract 30 percent more condensate than a simple Joule-Thompson expansion. Gas transferred to St. Fergus is 80 percent methane with a nett calorific value of 1000 BTU/SCF and a water dew point of −20°F at 1700 psig.

OVERALL PIPER GAS SYSTEM (See Figure 1)

At a crude production rate of 200,000 B/D the gas evolved at initial separation totals 75 MMSCF/D. The gas oil separation takes place at 150 psig. For entry to the Frigg system the gas must be processed and compressed to 1700 psig. In future 2100 psig will be required when the Frigg pipeline pressure is increased.

The first stage of compression is provided by centrifugal machines which discharge the gas at 650 psig. Cooling of the gas in sea water exchangers provides some condensate at this point. The major part of the gas processing then takes place between the first and second stages of reciprocating compressors. After compression to 1600 psig in the first stage the gas is dehydrated and the heavier components are condensed out by auto refrigeration. Recompression to export pipeline pressure of 1700 psig takes place in the second stage of the reciprocating machines.