bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and Molecular Characterization of Ataxia with Oculomotor Apraxia Patients In Saudi Arabia
Authors: Bohlega Saeed A , Shinwari Jameela M , Al Sharif Latifa J , Khalil Dania S , Alkhairallah Thamer S , Al Tassan Nada A
Published: February 2011

Background

Autosomal recessive ataxias represent a group of clinically overlapping disorders. These include ataxia with oculomotor apraxia type1 (AOA1), ataxia with oculomotor apraxia type 2 (AOA2) and ataxia-telangiectasia-like disease (ATLD). Patients are mainly characterized by cerebellar ataxia and oculomotor apraxia. Although these forms are not quite distinctive phenotypically, different genes have been linked to these disorders. Mutations in the APTX gene were reported in AOA1 patients, mutations in SETX gene were reported in patients with AOA2 and mutations in MRE11 were identified in ATLD patients. In the present study we describe in detail the clinical features and results of genetic analysis of 9 patients from 4 Saudi families with ataxia and oculomotor apraxia.

Methods

This study was conducted in the period between 2005-2010 to clinically and molecularly characterize patients with AOA phenotype. Comprehensive sequencing of all coding exons of previously reported genes related to this disorder (APTX, SETX and MRE11).

Results

A novel nonsense truncating mutation c.6859 C > T, R2287X in SETX gene was identified in patients from one family with AOA2. The previously reported missense mutation W210C in MRE11 gene was identified in two families with autosomal recessive ataxia and oculomotor apraxia.

Conclusion

Mutations in APTX , SETX and MRE11 are common in patients with autosomal recessive ataxia and oculomotor apraxia. The results of the comprehensive screening of these genes in 4 Saudi families identified mutations in SETX and MRE11 genes but failed to identify mutations in APTX gene.
Design and implementation of the canadian kidney disease cohort study (CKDCS): A prospective observational study of incident hemodialysis patients
Authors: Bello Aminu K , Thadhani Ravi , Hemmelgarn Brenda , Klarenbach Scott , Gill John , Chan Christopher , Zimmerman Deborah , Holmes Daniel , Cembrowski George , Opgenorth Dawn , Sibrian Rafael , Karkhaneh Mohammad , Tiv Sophanny , Wiebe Natasha , Tonelli Marcello
Published: February 2011

Background

Many nephrology observational studies use renal registries, which have well known limitations. The Canadian Kidney Disease Cohort Study (CKDCS) is a large prospective observational study of patients commencing hemodialysis in five Canadian centers. This study focuses on delineating potentially reversible determinants of adverse outcomes that occur in patients receiving dialysis for end-stage renal disease (ESRD).

Methods/Design

The CKDCS collects information on risk factors and outcomes, and stores specimens (blood, dialysate, hair and fingernails) at baseline and in long-term follow-up. Such specimens will permit measurements of biochemical markers, proteomic and genetic parameters (proteins and DNA) not measured in routine care. To avoid selection bias, all consenting incident hemodialysis patients at participating centers are enrolled, the large sample size (target of 1500 patients), large number of exposures, and high event rates will permit the exploration of multiple potential research questions.

Preliminary Results

Data on the baseline characteristics from the first 1074 subjects showed that the average age of patients was 62 (range; 50-73) years. The leading cause of ESRD was diabetic nephropathy (41.9%), and the majority of the patients were white (80.0%). Only 18.7% of the subjects received dialysis in a satellite unit, and over 80% lived within a 50 km radius of the nearest nephrologist's practice.

Discussion

The prospective design, detailed clinical information, and stored biological specimens provide a wealth of information with potential to greatly enhance our understanding of risk factors for adverse outcomes in dialysis patients. The scientific value of the stored patient tissue will grow as new genetic and biochemical markers are discovered in the future.
Leiomyosarcoma with partial rhabdomyoblastic differentiation: First case report of primary cardiac origin
Authors: Okubo Yoichiro , Shibuya Kazutoshi , Namiki Atsushi , Takamura Kazuhisa , Kameda Noriaki , Nemoto Tetsuo , Mitsuda Aki , Wakayama Megumi , Shinozaki Minoru , Hiruta Nobuyuki , Kitahara Kanako , Ishiwatari Takao , Yamazaki Junichi
Published: February 2011

Background

Leiomyosarcoma occurring as a primary cardiac tumor has been known as an extremely rare condition. Previous studies of leiomyosarcoma with rhabdomyoblastic differentiation have conducted to those arisen from another site, and they indicated a poorer prognosis of this tumor.

Case presentation

A 69-year-old woman was referred to our hospital for an operation concerning umbilical hernia. Subsequent imaging examinations before an operation indicated the presence of primary cardiac malignant tumor due to its atypical shape. And then, it was surgically removed. Histopathologically, tumor cells consisted of two different types: spindle and polyhedral cells. Immunohistochemically, it is interesting to note that 2.1% of spindle cells and 23.1% of polyhedral cells showed positive reactivity for myogenin. Furthermore, we performed double-immunostaining for alpha-smooth muscle actin (SMA) and myogenin. The rates of alpha-SMA and myogenin double negative, alpha-SMA single positive, myogenin single positive, and alpha-SMA and myogenin double positive in spindle cells were estimated as 69.1%, 28.8%, 1.1% and 1.0%, respectively. In contrast, the rates in polyhedral cells were estimated as 76.9%, 0.0%, 23.1%, and 0.0%, respectively.

Conclusion

Our immunohistochemical evaluation suggested that rhabdomyoblastic differentiation in leiomyosarcoma might be generated not only by de novo generation from mesenchymal cells. To the best of our knowledge, this is the first case of primary cardiac leiomyosarcoma with partial rhabdomyoblastic differentiation.
Predictors of consistent condom use based on the Information-Motivation-Behavioral Skills (IMB) model among female sex workers in Jinan, China
Authors: Zhang Hua , Liao Meizhen , Nie Xijuan , Pan Rongjian , Wang Chuangxin , Ruan Shiman , Zhang Changqing , Tao Xiaorun , Kang Dianmin , Jiang Baofa
Published: February 2011

Background

Female commercial sex workers (FSWs) are at high risk of human immunodeficiency virus (HIV) transmission in China. This study was designed to examine the predictors of condom use with clients during vaginal intercourse among FSWs based on the Information-Motivation-Behavioral Skills (IMB) model and to describe the relationships between IMB model constructs.

Methods

A cross-sectional study was conducted in Jinan of Shandong Province, from May to October, 2009. Participants (N = 432) were recruited using Respondent-Driven Sampling (RDS). A self-administered questionnaire was used to collect data. Structural equation modeling was used to assess the IMB model.

Results

A total of 427 (98.8%) participants completed their questionnaires. Condom use was significantly predicted by social referents support, experiences with and attitudes toward condoms, self-efficacy, and health behaviors and condom use skills. Significant indirect predictors of condom use mediated through behavioral skills included HIV knowledge, social referents support, and substance use.

Conclusions

These results suggest that the IMB model could be used to predict condom use among Chinese FSWs. Further research is warranted to develop preventive interventions on the basis of the IMB model to promote condom use among FSWs in China.
High cell density cultivation of Escherichia coli K4 in a microfiltration bioreactor: a step towards improvement of chondroitin precursor production
Authors: Restaino Odile Francesca , Cimini Donatella , De Rosa Mario , Catapano Angela , De Rosa Mario , Schiraldi Chiara
Published: February 2011

Background

The bacteria Escherichia coli K4 produces a capsular polysaccharide (K4 CPS) whose backbone is similar to the non sulphated chondroitin chain. The chondroitin sulphate is one of the major components of the extra-cellular matrix of the vertebrate connective tissues and a high value molecule, widely employed as active principle in the treatment of osteoarthritis. It is usually obtained by extraction from animal tissues, but the risk of virus contaminations, as well as the scarceness of raw material, makes this productive process unsafe and unable to satisfy the growing market demand. In previous studies a new biotechnological process to produce chondroitin from Escherichia coli K4 capsular polysaccharide was investigated and a 1.4 g·L-1 K4 CPS concentration was reached using fed-batch fermentation techniques. In this work, on the trail of these results, we exploited new fermentation strategies to further improve the capsular polysaccharide production.

Results

The inhibitory effect of acetate on the bacterial cells growth and K4 CPS production was studied in shake flask conditions, while a new approach, that combined the optimization of the feeding profiles, the improvement of aeration conditions and the use of a microfiltration bioreactor, was investigated in three different types of fermentation processes. High polysaccharide concentrations (4.73 ± 0.2 g·L-1), with corresponding average yields (0.13 ± 0.006 gK4 CPS·gcdw
-1), were obtained; the increase of K4 CPS titre, compared to batch and fed-batch results, was of 16-fold and 3.3-fold respectively, while average yield was almost 3.5 and 1.4 fold higher.

Conclusion

The increase of capsular polysaccharide titre confirmed the validity of the proposed fermentation strategy and opened the way to the use of the microfiltration bioreactor for the biotechnological production of chondroitin.
Purification and biochemical characterization of pancreatic phospholipase A2 from the common stingray Dasyatis pastinaca
Authors: Bacha Abir Ben , Karray Aida , Bouchaala Emna , Gargouri Youssef , Ali Yassine Ben
Published: February 2011

Background

Mammalian sPLA2-IB are well characterized. In contrast, much less is known about aquatic ones. The aquatic world contains a wide variety of living species and, hence represents a great potential for discovering new lipolytic enzymes.

Results

A marine stingray phospholipase A2 (SPLA2) was purified from delipidated pancreas. Purified SPLA2, which is not glycosylated protein, was found to be monomeric protein with a molecular mass of 14 kDa. A specific activity of 750 U/mg for purified SPLA2 was measured at optimal conditions (pH 8.5 and 40 °C) in the presence of 4 mM NaTDC and 8 mM CaCl2 using PC as substrate. The sequence of the first twenty first amino-acid residues at the N-terminal extremity of SPLA2 was determined and shows a close similarity with known mammal and bird pancreatic secreted phospholipases A2. SPLA2 stability in the presence of organic solvents, as well as in acidic and alkaline pH and at high temperature makes it a good candidate for its application in food industry.

Conclusions

SPLA2 has several advantageous features for industrial applications. Stability of SPLA2 in the presence of organic solvents, and its tolerance to high temperatures, basic and acidic pH, makes it a good candidate for application in food industry to treat phospholipid-rich industrial effluents, or to synthesize useful chemical compounds.
Characterization of silicon heterojunctions for solar cells
Authors: Kleider Jean-Paul , Alvarez Jose , Ankudinov Alexander Vitalievitch , Gudovskikh Alexander Sergeevitch , Gushchina Ekaterina Vladimirovna , Labrune Martin , Maslova Olga Alexandrovna , Favre Wilfried , Gueunier-Farret Marie-Estelle , Roca i Cabarrocas Pere , Terukov Eugene Ivanovitch
Published: February 2011

Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that show a large interface conductance. It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions. These are intimately related to the band offsets, which allows us to determine these parameters with good precision.
Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals
Authors: Gresback Ryan , Hue Ryan , Gladfelter Wayne L , Kortshagen Uwe R
Published: February 2011

Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown around the plasma-synthesized InP NCs in a liquid phase reaction. Photoluminescence with quantum yields as high as 15% were observed for the InP/ZnS core-shell NCs.
The encapsulation effect of UV molecular absorbers into biocompatible lipid nanoparticles
Authors: Lacatusu Ioana , Badea Nicoleta , Murariu Alina , Meghea Aurelia
Published: February 2011

The efficiency of a cosmetic product depends not only on the active ingredients, but also on the carrier system devoted to improve its bioavailability. This article aims to encapsulate two couples of UV molecular absorbers, with a blocking action on both UV-A and UV-B domains, into efficient lipid nanoparticles. The effect of encapsulation on the specific properties such as sun protection factor and photostability behaviour has been demonstrated. The lipid nanoparticles with size range 30-350 nm and a polydispersity index between 0.217 and 0.244 are obtained using a modified high shear homogenisation method. The nanoparticles had spherical shapes with a single crystallisation form of lipid matrices characteristic for the least ordered crystal structure (α-form). The in vitro determination of photoprotection has led to high SPF ratings, with values of about 20, which assure a good photoprotection and filtering about 95% of UV radiation. The photoprotection effect after irradiation stage was observed to be increased more than twice compared to initial samples as a result of isomerisation phenomena. All the results have shown that good photoprotection effect and improved photostability could be obtained using such sunscreen couples, thus demonstrating that UV absorbers-solid lipid nanoparticles are promising carriers for cosmetic formulations.
Nanosilver induces minimal lung toxicity or inflammation in a subacute murine inhalation model
Authors: Stebounova Larissa V , Adamcakova-Dodd Andrea , Kim Jong Sung , Park Heaweon , O'Shaughnessy Patrick T , Grassian Vicki H , Thorne Peter S
Published: February 2011

Background

There is increasing interest in the environmental and health consequences of silver nanoparticles as the use of this material becomes widespread. Although human exposure to nanosilver is increasing, only a few studies address possible toxic effect of inhaled nanosilver. The objective of this study was to determine whether very small commercially available nanosilver induces pulmonary toxicity in mice following inhalation exposure.

Results

In this study, mice were exposed sub-acutely by inhalation to well-characterized nanosilver (3.3 mg/m3, 4 hours/day, 10 days, 5 ± 2 nm primary size). Toxicity was assessed by enumeration of total and differential cells, determination of total protein, lactate dehydrogenase activity and inflammatory cytokines in bronchoalveolar lavage fluid. Lungs were evaluated for histopathologic changes and the presence of silver. In contrast to published in vitro studies, minimal inflammatory response or toxicity was found following exposure to nanosilver in our in vivo study. The median retained dose of nanosilver in the lungs measured by inductively coupled plasma - optical emission spectroscopy (ICP-OES) was 31 μg/g lung (dry weight) immediately after the final exposure, 10 μg/g following exposure and a 3-wk rest period and zero in sham-exposed controls. Dissolution studies showed that nanosilver did not dissolve in solutions mimicking the intracellular or extracellular milieu.

Conclusions

Mice exposed to nanosilver showed minimal pulmonary inflammation or cytotoxicity following sub-acute exposures. However, longer term exposures with higher lung burdens of nanosilver are needed to ensure that there are no chronic effects and to evaluate possible translocation to other organs.
Mathematical model of uptake and metabolism of arsenic(III) in human hepatocytes - Incorporation of cellular antioxidant response and threshold-dependent behavior
Authors: Stamatelos Spyros K , Brinkerhoff Christopher J , Isukapalli Sastry S , Georgopoulos Panos G
Published: February 2011

Background

Arsenic is an environmental pollutant, potent human toxicant, and oxidative stress agent with a multiplicity of health effects associated with both acute and chronic exposures. A semi-mechanistic cellular-level toxicokinetic (TK) model was developed in order to describe the uptake, biotransformation and clearance of arsenical species in human hepatocytes. Notable features of this model are the incorporation of arsenic-glutathione complex formation and a "switch-like" formulation to describe the antioxidant response of hepatocytes to arsenic exposure.

Results

The cellular-level TK model applies mass action kinetics in order to predict the concentrations of trivalent and pentavalent arsenicals in hepatocytes. The model simulates uptake of arsenite (iAsIII) via aquaporin isozymes 9 (AQP9s), glutathione (GSH) conjugation, methylation by arsenic methyltransferase (AS3MT), efflux through multidrug resistant proteins (MRPs) and the induced antioxidant response via thioredoxin reductase (TR) activity. The model was parameterized by optimization of model estimates for arsenite (iAsIII), monomethylated (MMA) and dimethylated (DMA) arsenicals concentrations with time-course experimental data in human hepatocytes for a time span of 48 hours, and dose-response data at 24 hours for a range of arsenite concentrations from 0.1 to 10 μM. Global sensitivity analysis of the model showed that at low doses the transport parameters had a dominant role, whereas at higher doses the biotransformation parameters were the most significant. A parametric comparison of the TK model with an analogous model developed for rat hepatocytes from the literature demonstrated that the biotransformation of arsenite (e.g. GSH conjugation) has a large role in explaining the variation in methylation between rats and humans.

Conclusions

The cellular-level TK model captures the temporal modes of arsenical accumulation in human hepatocytes. It highlighted the key biological processes that influence arsenic metabolism by explicitly modelling the metabolic network of GSH-adducts formation. The parametric comparison with the TK model developed for rats suggests that the variability in GSH conjugation could have an important role in inter-species variability of arsenical methylation. The TK model can be incorporated into larger-scale physiologically based toxicokinetic (PBTK) models of arsenic for improving the estimates of PBTK model parameters.
Upregulation of microRNA-451 increases cisplatin sensitivity of non-small cell lung cancer cell line (A549)
Authors: Bian Hai-Bo , Pan Xuan , Yang Jin-Song , Wang Zhao-Xia , De Wei
Published: February 2011

Background

Recently, miR-451 as a tumor suppressor has been reported in other studies. However, whether miR-451 can affect the sensitivity of non-small cell lung cancer (NSCLC) cells to cisplatin (DDP) remains unclear. The aim of this study is to evaluate the roles of miR-451 in the sensitivity of NSCLC cells to DDP.

Methods

Quantitative RT-PCR assay was performed to detect the expression of miR-451 in 10 pairs of NSCLC and noncancerous tissue samples. pcDNA-GW/EmGFP-miR-451 was stably transfected into NSCLC cell line (A549). Then, the effects of miR-451 upregulation on growth, colony formation and apoptosis of A549 cells were investigated. Finally, the effects of miR-451 upregulation on in vitro and in vivo sensitivity of A549 cells of DDP were also determined.

Results

The level of miR-451 expression in NSCLC tissues was significantly higher than that in corresponding noncancerous tissues. Ectopic overexpression of miR-451 could significantly inhibit growth and induce apoptosis of A549 cells. Moreover, ectopic overexpression of miR-451 could sensitize A549 cells to DDP possibly by increasing DDP-induced apoptosis which might be associated with the inactivation of Akt signaling pathway.

Conclusions

This study demonstrated for the first time that combination of DDP application with miR-451 upregulation might be a potential strategy for the treatment of human NSCLC.
Insulin-Induced Oxidative Stress Up-Regulates Heme Oxygenase-1 via Diverse Signaling Cascades in the C2 Skeletal Myoblast Cell Line
Authors: Aggeli Ioanna-Katerina , Theofilatos Dimitris , Beis Isidoros , Gaitanaki Catherine
Published: February 2011

Impaired insulin sensitivity (insulin resistance) is a common denominator in many metabolic disorders, exerting pleiotropic effects on skeletal muscle, liver, and adipose tissue function. Heme oxygenase-1 (HOX-1), the rate-limiting enzyme in heme catabolism, has recently been shown to confer an antidiabetic effect while regulating cellular redox-buffering capacity. Therefore, in the present study, we probed into the mechanisms underlying the effect of insulin on HOX-1 in C2 skeletal myoblasts. Hence, insulin was found to suppress C2 myoblasts viability via stimulation of oxidative stress, with HOX-1 counteracting this action. Insulin induced HOX-1 expression in a time- and dose-dependent manner, an effect attenuated by selective inhibitors of ERK1/2 (PD98059), Src (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d] pyrimidine), and c-Jun terminal kinases 1 and 2 (SP600125) pathways. Furthermore, nuclear factor-κB role in insulin-induced HOX-1 up-regulation was verified, with ERK1/2, Src, and c-Jun terminal kinases 1 and 2 mediating p65-nuclear factor-κB subunit phosphorylation. Overall, our novel findings highlight for the first time the transduction mechanisms mediating HOX-1 induction in insulin-treated C2 myoblasts. This effect was established to be cell type specific because insulin failed to promote HOX-1 expression in HepG2 hepatoma cells. Deciphering the signaling networks involved in insulin-stimulated HOX-1 up-regulation is of prominent significance because it may potentially contribute to elucidation of the mechanisms involved in associated metabolic pathologies.
Photoinduced Triplet States of Photoconductive TTF Derivatives Including a Fluorescent Group
Authors: Furukawa Ko , Sugishima Yasuo , Fujiwara Hideki , Nakamura Toshikazu
Published: February 2011

The spin dynamics of photoconductive tetrathiafulvalene (TTF) derivatives containing 2,5-diphenyl-1,3,4-oxadiazole (PPD) was examined using time-resolved electron spin resonance (TR-ESR) spectroscopy. TR-ESR signals of a frozen solution sample under visible excitation were attributed to the excited triplet state T1, which was populated via intersystem crossing from the excited singlet state S1 as confirmed by TR-ESR spectral simulations. From DFT calculations, the spin-density distribution of the T1 state was found to be concentrated around the linker between the TTF and PPD molecules.
Convenient Synthesis of Dibenzo[a,h]anthracenes and Picenes via C–H Arylation of Acetophenones with Arenediboronates
Authors: Kitazawa Kentaroh , Kochi Takuya , Nitani Masashi , Ie Yutaka , Aso Yoshio , Kakiuchi Fumitoshi
Published: February 2011

A new convenient method for the synthesis of dibenzo[a,h]anthracenes and picenes using ruthenium-catalyzed regioselective C–H arylation of aromatic ketones has been developed. Acetophenone derivatives and 1,4-benzenediboronates were coupled in 2:1 ratios to form p-terphenyl derivatives. Conversion of the acetyl group to an ethynyl group, followed by cycloaromatization provided the desired fused aromatic compounds. An organic field-effect transistor fabricated from one of these products gave moderate hole mobility.
Evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser for HbA1c
Authors: Weykamp Cas , Lenters-Westra Erna , van der Vuurst Hans , Slingerland Robbert , Siebelder Carla , Visser-Dekkers Willeke
Published: February 2011

Background: We report an evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser (HA-8180V), the fifth generation Menarini/ARKRAY ion-exchange HPLC for the measurement of HbA1c.

Methods: We evaluated the analytical performance, the measurement of haemoglobin variants and the performance in comparison to major analytical methods.

Results: Within-run, between-run and total CV were 0.2%, 0.4% and 0.7% at low HbA1c concentrations and 0.2%, 0.2% and 0.4% at high HbA1c concentrations, respectively. Trueness revealed a maximum deviation of 0.8 mmol/mol (IFCC units) or 0.1% (NGSP units) over the relevant analytical range. Linearity, carry-over and linear drift were excellent. Labile-HbA1c, carbamylated haemoglobin, icteric samples and variation in hematocrit did not affect HbA1c outcome. Haemoglobin variants AS, AC and F do not affect HbA1c outcome and are explicitly identified and correctly quantified. HbA1c can not be measured in samples with AE and AD, but these variants are identified correctly. In comparison to other methods used at present, the HA-8180V shows excellent performance.

Conclusions: The HA-8180V performs at a high level and is fit for any clinical application.
A case of primary aldosteronism in pregnancy: do LH and GNRH receptors have a potential role in regulating aldosterone secretion?
Authors: Albiger N M , Sartorato P , Mariniello B , Iacobone M , Finco I , Fassina A , Mantero F
Published: February 2011

Objective

The mechanisms inducing steroidogenesis in primary aldosteronism (PA) remain poorly defined. It was recently demonstrated that some G-protein-coupled receptors are abnormally expressed in aldosterone-producing adenomas (APA). We evaluated the potential role of LH and GNRH receptors (LHR (or LHCGR) and GNRHR) in regulating aldosterone secretion in a patient with APA arising during pregnancy (index case) and in a subset of other patients with PA.

Patients and methods

GNRH test was performed in the index case, 11 other PA, and 5 controls. GNRHR and LHR expressions were examined in 23 APA and 6 normal tissues.

Results

Aldosterone response increased significantly (114%) in the index case after GNRH test was performed preoperatively, while it was blunted after adrenalectomy. Aldosterone also increased after human chorionic gonadotropin and triptorelin stimulation. A partial aldosterone response to GNRH was observed in other 7/11 PA, while a significant response was observed in two patients. Controls did not respond to GNRH test.

GNRHR was overexpressed and LHR expression was moderate in the APA tissue from the index case. Moreover, LHR was found in normal adrenals and overexpressed in 6/22 APA. GNRHR was overexpressed in 6/22 APA, 2 of them with a 95- and 109-fold higher expression than normal. A correlation between the clinical and molecular findings was observed in five out of seven patients.

Conclusion

We describe a case of PA diagnosed during pregnancy, which appeared to correlate with aberrant LHR and GNRHR expression. Our findings suggest that a subset of patients with PA has aberrant LHR and GNRHR expression, which could modulate aldosterone secretion.
A novel HESX1 splice mutation causes isolated GH deficiency by interfering with mRNA processing
Authors: Vivenza Daniela , Godi Michela , Faienza Maria Felicia , Mellone Simona , Moia Stefania , Rapa Anna , Petri Antonella , Bellone Simonetta , Riccomagno Stefania , Cavallo Luciano , Giordano Mara , Bona Gianni
Published: February 2011

Objective

Mutations inHESX1represent a rare cause of GH deficiency (GHD) associated with a broad spectrum of other anomalies. We searched for causative mutations in a cohort of 244 Italian patients affected by combined and isolated GHD (IGHD).

Methods

TheHESX1gene-coding region and exon–intron boundaries were screened by denaturing HPLC scanning.

Results

A novel mutation adjacent to the invariant donor splice site of intron 2 (c.357+3G>A) was identified at the heterozygous state in an IGHD patient. Thein vitroandin vivomRNA analysis of the wild-typeHESX1allele revealed the presence of the whole cDNA and two isoforms lacking exon 2 and exons 2–3 respectively. The mutantHESX1allele yielded only two splicing products, the whole cDNA and the cDNA missing exons 2–3, whereas the mRNA lacking exon 2 was absent. Anin vitroassay demonstrated that the exon 2-deleted mRNA, predicting a prematurely truncated protein, is subjected to nonsense-mediated mRNA decay (NMD).

Conclusions

Thec.357+3G>Amutation prevents the generation of one of the alternative isoforms normally produced by the wild-type allele, predicting a truncated HESX1 protein. The mutation is likely to cause IGHD in the heterozygous patient by interfering with the downregulation ofHESX1expression mediated by alternative splicing and NMD.

Our results open new insight into the mechanism ofHESX1regulation suggesting that the coupling of alternative splicing and NMD might play a fundamental role in directing theHESX1expression, and that the alteration of this process might lead to severe consequences.
Investigation of Pressure Monitoring Methods for Xing1-2 Field, Daqing
Authors: Zhang X. , Gao P. , Yin D.
Published: February 2011

In this research, both reservoir simulation and well testing were employed to investigate the average reservoir pressure in the Xing 1-2, a multilayer sandstone reservoir. The concrete methods included the well testing, Peaceman, and volumetric weighted average method (VWA). The average reservoir pressures for the last three years of the monitoring wells were calculated. The results showed diversities among three methods at each well pattern. The factors which caused diversities in three methods have been categorized, like the geological uncertainties, production impact, the difference in mathematical methods, etc. The wells in low pressure zones were detected and analyzed. By reducing the influence of referenceless interpretations, the system provided more accurate interpretations. The results were also used to optimize the monitored wells and to offer reference for the improvement of the injection and production system.
The Use of Wireline Formation Tester for Optimization of Conventional Well Test Design and Interpretation
Authors: Kumar Vikash , Dunlap James , Klimentos Theodore , Khan Zuber A. , Farooqui M. Y.
Published: February 2011

During the exploration and appraisal phases field data is collected for the determination of reservoir parameters which will govern the Field Development and production strategy. Permeability-thickness, hydrocarbon properties and reservoir extent are critical parameters acquired during this phase which are used to evaluate expected well and reservoir performance. Dynamic Flow tests, combined with Downhole Fluid Analysis and fluid samples are commonly used to obtain this information. The most common flow tests today use either Wireline Formation Testers (WFT) for small scale tests, or Drill Stem Tests (DST) for larger scale flow tests. This paper will describe a workflow in which the information acquired from the small scale WFT tests can be used to optimize the design and execution of the larger, and typically more costly, DST’s. The ultimate goal of the workflow is to increase the value of the information obtained, and the overall success rate of the DST’s performed.
Accurate Inflow Profile Prediction of Horizontal Wells Using a Newly Developed Coupled Reservoir and Wellbore Flow Equations
Authors: Kabir Akim , Vargas Jose A.
Published: February 2011

Despite their widespread use, horizontal wells continue to underperform compared to our expectations. This is mainly due to lack of our understanding and ability to predict accurate inflow profile as a result of pressure drop along the wellbore. Stand- alone inflow equations do not calculate accurate inflow profile. In order to get the best performance from a horizontal well, a uniform inflow profile achievement is important. This cannot be addressed unless the inflow profile is quantified.

In this work we describe coupling of some analytical reservoir flow models with wellbore flow models for predicting ac- curate inflow profile of long horizontal wells. S. D. Joshi and Babu-Odeh inflow equation options have been implemented in this coupled solution. Continuity equations are used to calculate pressure drop in the wellbore. A coupling algorithm has been proposed which converges reasonably quickly giving accurate picture of the inflow profile. Results obtained from this work have been compared with some published work which is encouraging. Also results of a few case studies have been discussed which show the effect of a few completion/ fluid parameters on pressure & flux profile of these (horizontal) wells. The ulti- mate goal of this work is to come up with a stand-alone computer program which will be able to model not only the inflow performance relationship of these wells, but also will be able to come up with detailed inflow profiles along the completed interval of horizontal wells for various completion options with varying parameters.
Application of Telemetry Technology In High-Pressure Wells To Improve Data Accuracy in Drill Stem Tests
Authors: Haddad Josmar , Salguero Alejandro , Jaimes Carrie
Published: February 2011

Drill-stem testing (DST) has been used for many years in the oilfield to establish reliable reservoir characterization. The DST data are used to provide estimated production, fluid analysis, and to help design the final completion and production facilities.

More recently, discoveries in abnormal pressure gradients and deep formations have not only pushed the capabilities of traditional equipment and procedures, but also increased the safety hazards inherent to DST operations. At surface, high pressures, the presence of H2S, and toxic well fluids increase the difficulty in deployment of real-time data acquisition and sampling equipment via wireline. Downhole, the high hydrostatic pressures normally found in deep environments can hinder the operation of the downhole tools. Often, to achieve high hydrostatic pressures, the operator is forced to use drilling muds which may have very low pressure transmissibility and solids problems that interfere with annulus-pressure/pulse-response tools.

The need to improve the quality of information gathered during DSTs in hostile environments has driven a major oilfield engineering company to research concepts that could improve capabilities of traditional DST systems.

This research led to the development of a novel telemetry system that uses acoustic bi-directional acoustic transmission through the tubing string. This system, compact and easy to deploy into the well, provides real-time data-acquisition flexibility in various depths in the string, enabling the constant monitoring of the wellbore conditions throughout the DST. It’s design, applications, and ability to simplify job procedures, reduce risks, and improve quality of information when linked to data acquisition and tool operation, will be the focus of this paper.

This new system provides greater efficiency in acquiring data in deeper, high-pressure DST environments than are currently possible with the standard methods.
Comparing Wireline Formation Tester Derived Productivity Index to Drill Stem Test
Authors: Khong Chee Kin , Li Chen , Ayan Cosan , Xu Liqiang , Jun Cai , Guo Shusheng , Wang Wu Mu , Zhongtian Hao , Fuxi Pan , Zhongjian Tan , Jun Yang Hong
Published: February 2011

Drill stem test (DST) derived average effective permeability and productivity is our industry's accepted standard but DST expenses are not always justified especially in development wells. Although zonal contribution could be measured by production logging survey but this requires an additional well intervention operation and most likely interruption of production as well. Zonal productivity modeled correctly in a well is of immense value for reservoir management. In exploration well, accurate productivity index prior to DST is invaluable for operational planning, while in development well accurate productivity index is crucial for completion design.

If dynamic data is not available, zonal productivity had been estimated based on permeability derived from petrophysical log data. Single probe open-hole wireline formation tester (OH-WFT) pretest mobility is often used to calibrate log data estimated permeability. However, OH-WFT pretest almost always measure the invaded or drilling induced damaged zone and is at a scale much smaller than DST derived average permeability.

Interval Pressure Transient Test using wireline formation tester estimate permeability further away from invaded or drilling induced damaged zone provides a more accurate permeability measurement. Multi-probe or Single-probe WFT is an attractive option when borehole condition does not allow wireline formation tester with straddle packer (WFT-PA) operation.

For Single-probe WFT data, permeability anisotropy has to be assumed while permeability anisotropy can be calculated from Multi-probe or Packer-probe pressure data. WFT estimated permeability from pressure transient analysis allows zonal productivity to be calculated, utilizing also pressure, temperature, fluid data, zonal thickness, completed interval and formation dip data.

Log data modeled zonal productivity from static data had resulted in off-forecast compared to actual well performance. In this paper, multi-probe and packer-probe wireline formation tester permeability test is used to derive zonal productivity. This productivity estimate is compared to actual DST productivity index.
Case History: Continuous Improvement in a Staggered Drilling Campaign
Authors: Gordon Jeanette
Published: February 2011

This paper will compare the operational performance of appraisal / exploration wells in the East Timor Sea for a Joint Venture Group. The paper will review operations using three different rigs; one semi-submersible and two jack ups, each deploying a different wellhead configuration / method to drill exploration / appraisal wells in the same field.

A review of the performance improvements progressed by the operations team over the three years of the staggered project will be provided including;

Field breaking records for drilling performance Comparison of motor and RSS systems with tricone and PDC bits in the field The use of a vibration dampening tool to effect drilling performance BOP and riser running operations compared between the three different rigs Sidetracking operations along with recommendations

Three operational phases were focused upon during the review and these were; drilling 17.1/2" and 12.1/4" hole sections along with open hole sidetracking operations. Drilling performance, engineering planning lessons and recommendations are captured in this paper. A brief review of the costs of deviated wells utilizing subsea wellheads deployed from a semi-submersible rig in comparison to directional wells utilizing subsea wellheads deployed from a jack up, and deviated subsea wells utilizing surface wellheads will be overviewed as there is minimal comparison of these operations currently available in the literature.

The lessons and recommendations contained within this paper can be applied during the well planning stage of any project. A detailed review of performance has been undertaken which highlights the importance of the planning process in operational optimization along with the necessity of clearly defining the expected well outcome as a means of managing the economic success of a project.
ESP Performances for Gas-Lifted High Water Cut Wells
Authors: Bagci A. Suat , Kece Murat , Nava Jocsiris
Published: February 2011

Electrical Submersible Pumping (ESP) and Gas lift (GL) are a part of the long term production sustainability solutions in the fields with increasing water cuts, and depleting reservoir energy. In order to increase the production from this type of fields and sustain the field target rates, production optimization and revisiting of the artificial lift selection proves to be the best cost effective solution.

This paper summarizes the methodology used and the results of a review of artificial lift strategy in a brown field environment with severe gaslift constraints. Potential use of alternative artificial lift technologies in selected high water cut wells was justified. ESP were shown to provide particular advantages related to high water cut oil well applications and easy surveillance access in addition to operating flexibility for changing conditions.

Present GL flow conditions were simulated to determine the operating envelope and the conditions at which GL flow ceases. GL vs. ESP performance comparisons were then carried out for each well over their lifecycle. The incremental revenue and cost impact of ESPs were demonstrated. For all design cases, ESPs can match or exceed the GL performance in this case for the present, middle and late life cases.
Lightweight Water-Based Mud Using Glass Bubbles for Drilling a 6-in. Horizontal Section in a Gunung Kembang Development Well
Authors: Edwin Pratama , Syahriza Ghany R. , Yose Martin , Arga Purwanto
Published: February 2011

A Gunung Kembang drilling campaign recently drilled three wells with 1,510-, 525-, and 283-ft MD horizontal section lengths. The landing point of these wells is 3,200 ft TVD in limestone formations. Failures from the first and third wells resulted from a total-loss circulation problem, and drilling was stopped following an uncontrolled loss rate and a diesel-oil stock shortage.

Two suspected factors are believed to be the cause of loss circulation in Gunung Kembang: 1) depleted formation pressure, which recorded 6.8 ppg and led to a narrow margin of overbalance mud weight and minimum stability mud weight, and 2) the presence of natural fractures. This factor requires further discussion owing to the geomechanic study results, which predicted several azimuths that natural fractures will most likely encounter while drilling.

Water-based mud then becomes an option for drilling a 6-in. horizontal section in the Baturaja limestone formation, as water supply is almost unlimited and is easy to acquire. A non-damaging fluid in combination with a glass-bubble lightweight additive is proposed for drilling this section to 1,600 ft MD. To minimize the possibility of loss circulation, mud density is designed to be slightly higher than the formation pressure. The formation pressure is recorded at 6.8 ppg, thus the mud weight will be 6.9–7.1 ppg (17–50-psi overbalance) using glass bubbles (hollow-glass spheres).

A laboratory test regarding this mud system was conducted to determine the optimum concentration of glass bubbles in waterbased mud using the value of PV so as to affect ECD and surface circulating equipment reliability. A return permeability test was also conducted against the Baturaja limestone core sample with a 15% reduction in permeability. This result offers a better solution for the Gunung Kembang drilling campaign owing to its lower operational cost and that it is more environmental friendly.
Drive Down Costs at Surface: Eliminate Contingency Strings in Deepwater
Authors: Nunzi Paolo , Molaschi Claudio , Beattie Scott , Feasey Guy , Odell Al , Twardowski Eric
Published: February 2011

As the expense of deepwater drilling increases, efforts to eliminate or reduce non-productive time (NPT) can have a significant effect on overall costs. Current standard practices for installing surface casing strings involve multiple trips to first drill the hole section, and then run casing, land the wellhead, and cement. In many instances these casing seats are set shallower than is optimal due to anticipated hazards such as shallow gas or water flows and wellbore stability issues. Although with the current deepwater drilling model these practices are safe and reasonably efficient, they can limit the depth at which the casing can be set, as compared to the optimal depth with respect to pore pressures and fracture gradients.

The use of current proven Casing While Drilling (CWD) techniques has effectively reduced NPT in several key areas including: flat-time reduction, shallow hazard mitigation, minimized/eliminated lost circulation, and improved cement placement and bond. Additionally, CWD provides the opportunity to push casing seats deeper, thus potentially eliminating contingency strings. Current CWD methods have not been applied to subsea surface casing applications, primarily because of the challenge of simultaneous drilling-in and landing the high pressure wellhead without damaging the seal surfaces on the wellhead housings. Additionally, many wellhead running tools are not designed to carry drilling torque.

This paper discusses the benefits associated with drilling-in the surface casing in a subsea application. Introduced is a new CWD method and enabling technology that can significantly improve this phase of deepwater drilling operations. The complete process of drilling-in and running casing, landing the wellhead, and cementing can be achieved in a single trip. The benefits of CWD and features of the new technology are presented. When compared with current deepwater "best practice" models, an immediate 25% time savings is achievable. This technology also enables the utilization of less expensive floating rigs for cost reduction by batch drilling and setting of surface casing.
Rapid Prediction of Carbon Dioxide and Nitrogen Adsorption Behavior at Cryogenic Temperatures
Authors: Bahadori A. , Vuthaluru H. B.
Published: February 2011

Conventionally, CO2 removal requires the use of a water-based amine solution and large absorber and regeneration towers. The capital and ongoing operational costs for this process are substantial, and the use (regeneration and disposal) of the amine solution can be problematic from the perspectives of both safety and the environment. Nitrogen can also be a problematic impurity in natural gas. In this work, a newly developed method is applied to accurately predict the carbon dioxide and nitrogen adsorption isotherms at low temperatures and pressures up to saturation for a com1mercial carbon molecular sieve as a function of temperature and partial pressure of these components. Accurate prediction of such data is useful in evaluating the feasibility of using pressure swing adsorption to separate nitrogen and carbon dioxide from natural gases at cryogenic temperatures for carbon dioxide and nitrogen. The proposed method showed consistently accurate results across the investigated wide pressure and temperature ranges with an average absolute deviation of less than 1% for both nitrogen and carbon dioxide. This is expected to benefit in making informed design decisions for the selection of adsorbents for a given application in any process industry.