bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Dexmedetomidine in the Pediatric Intensive Care Unit
Authors: Buck Marcia L. , Willson Douglas F. 
Published: December 2007

Study Objective. To determine the safety, effectiveness, and dosing of dexmedetomidine in intensive care infants and children who require sedation, and the rationale for patient selection.Design. Prospective observational study.Setting. Eleven‐bed pediatric intensive care unit in a university‐affiliated children's hospital.Patients. Seventeen infants and children who received dexmedetomidine consecutively between May 4, 2005, and May 4, 2006.Measurements and Main Results. Data were collected on demographics, blood pressure and heart rate measurements, and adverse effects. The rationale for dexmedetomidine use, its dosing, use of other sedatives, and treatment duration were also recorded. Twenty treatment courses in 17 patients (median age 5 mo, range 1 mo‐17 yrs) were evaluated. Ten patients (59%) had chronic neurologic impairments (including Down syndrome in nine [53%]). Thirteen (76%) had undergone cardiac surgery, two (12%) had respiratory failure, one (6%) had endocarditis, and one (6%) had undergone scoliosis repair. In 15 (75%) of 20 cases, dexmedetomidine was started to minimize the use of midazolam before extubation; in 13 (87%) of these cases, the patients were extubated within 24 hours. The remaining patients could not tolerate midazolam, and dexmedetomidine was used as an alternative. No loading doses were given. The mean ± SD starting dose was 0.2 ± 0.2 μg/kg/hour, with a maximum of 0.5 ± 0.2 μg/kg/hour. Mean ± SD duration was 32 ± 21 hours (range 3–75 hrs); 10 courses exceeded 24 hours. Mean arterial pressures before and after starting treatment were not significantly different (p=0.76), nor were values at discontinuation (p=0.31) or 12 hours later (p=0.29). No significant differences were noted in heart rate at the start (p=0.09), at discontinuation (p=0.06), or 12 hours later (p=0.17). One patient (6%) developed hypotension; no other adverse effects were noted.Conclusion. With careful patient selection and a conservative approach to dosing, dexmedetomidine was a useful sedative in children requiring mechanical ventilation. It allowed for a reduction or elimination of other sedatives, and it was particularly useful in children with chronic neurologic impairments. Dexmedetomidine was well tolerated, with no clinically significant effects on blood pressure or heart rate.
Pharmacokinetics of an Indinavir‐Ritonavir‐Fosamprenavir Regimen in Patients with Human Immunodeficiency Virus
Authors: Ofotokun Ighovwerha , Acosta Edward P. , Lennox Jeffrey L. , Pan Yi , Easley Kirk A. 
Published: December 2007

Study Objective. To evaluate the pharmacokinetic compatibility of a ritonavir‐boosted indinavir‐fosamprenavir combination among patients with human immunodeficiency virus (HIV).Design. Single‐center, nonrandomized, prospective, multiple‐dose, two‐phase pharmacokinetic study.Setting. University research center.Patients. Eight adult patients with HIV infection who had been receiving and tolerating indinavir 800 mg‐ritonavir 100 mg twice/day for at least 2 weeks.Intervention. After 12‐hour pharmacokinetic sampling was performed on all patients (period A), fosamprenavir (a prodrug of amprenavir) 700 mg twice/day was coadministered for 5 days, with a repeat 12‐hour pharmacokinetic sampling performed on the fifth day (period B).Measurements and Main Results. Pharmacokinetic parameters were determined for indinavir, ritonavir, and amprenavir: area under the concentration‐time curve from time 0 to 12 hours after dosing (AUC0–12), maximum plasma concentration (Cmax), and 12‐hour plasma concentration (C12). For each parameter, the geometric mean, as well as the geometric mean ratio (GMR) comparing period B with period A, were calculated. Indinavir Cmax was lowered by 20% (GMR 0.80, 95% confidence interval [CI] 0.67‐0.96), AUC0–12 was lowered by 6% (GMR 0.94, 95% CI 0.74‐1.21), and C12 was increased by 28% (GMR 1.28, 95% CI 0.78‐2.10). Ritonavir AUC0–12 was 20% lower (GMR 0.80, 95% CI 0.54‐1.19), Cmax was 15% lower (GMR 0.85, 95% CI 0.55‐1.32), and C12 was 7% lower (GMR 0.93, 95% CI 0.49‐1.76). With the exception of indinavir Cmax, the changes in indinavir and ritonavir pharmacokinetic parameters observed after fosamprenavir coadministration were not statistically significant. The geometric means of amprenavir AUC0–12, Cmax, and C12 were 41,517 ngṁhour/ml (95% CI 30,317‐56,854 ngṁhr/ml), 5572 ng/ml (95% CI 4330–7170 ng/ml), and 2421 ng/ml (95% CI 1578–3712 ng/ml), respectively.Conclusion. The combination of indinavir 800 mg‐ritonavir 100 mg‐fosamprenavir 700 mg twice/day appears to be devoid of a clinically significant drug‐drug interaction and should be evaluated as an alternative regimen in salvage HIV treatment. This combination may be suitable as part of a background regimen to optimize the therapeutic benefit of newer classes of antiretroviral agents such as the integrase and coreceptor inhibitors in the treatment of multidrug‐resistant viruses.
Prevalence of and Risk Factors for Dysglycemia in Patients Receiving Gatifloxacin and Levofloxacin in an Outpatient Setting
Authors: LaPlante Kerry L. , Mersfelder Tracey L. , Ward Kristina E. , Quilliam Brian J. 
Published: December 2007

Study Objectives. To assess the prevalence of dysglycemia (hypoglycemia or hyperglycemia) associated with oral levofloxacin and gatifloxacin therapy in an outpatient setting, and to determine the characteristics of patients who developed dysglycemia while receiving either fluoroquinolone.Design. Retrospective medical record review.Setting. Outpatient clinic of a Veterans Affairs teaching hospital.Patients. A total of 1573 patients who received oral levofloxacin (343 patients), gatifloxacin (589 patients), or azithromycin (as a control, 641 patients) between June 1, 2004, and May 31, 2006.Measurements and Main Results. Dysglycemia occurred in 33 patients: 13 (2.2%), 9 (2.6%), and 11 (1.7%), respectively, of those in the gatifloxacin, levofloxacin, and azithromycin groups. Of 13 patients who experienced a hyperglycemic event, 11 (84.6%) had diabetes mellitus. After adjustment for confounding factors, neither levofloxacin nor gatifloxacin were associated with increased odds of developing a dysglycemic event compared with azithromycin. Multivariate analysis demonstrated that lack of downward dosage adjustment based on creatinine clearance (odds ratio [OR] 10.3, 95% confidence interval [CI] 3.8–27.6), presence of diabetes (OR 17.1, 95% CI 3.1–94.9), or treatment with insulin (OR 5.3, 95% CI 1.8–15.7) or sulfonylureas (OR 3.6, 95% CI 1.3–10.4) independently increased dysglycemia risk. Obesity (body mass index > 30 kg/m2) was independently protective (OR 0.22, 95% CI 0.09‐0.55) against dysglycemic events.Conclusion. Levofloxacin and gatifloxacin were not significantly associated with increased dysglycemic events compared with azithromycin. Lack of downward fluoroquinolone dosage adjustment for renal function, presence of diabetes, and treatment with insulin or sulfonylureas each independently increased the risk of dysglycemia. Obesity was independently protective against dysglycemia. More data are needed on the contributing effects of diabetes, fluoroquinolone dosage, and concomitant drug therapy so that an appropriate risk‐management strategy can be developed.
Tex19, a Mammalian-Specific Protein with a Restricted Expression in Pluripotent Stem Cells and Germ Line
Authors: Kuntz Sandra , Kieffer Emmanuelle , Bianchetti Laurent , Lamoureux Nicolas , Fuhrmann Guy , Viville Stéphane 
Published: December 2007

Abstract
Although the properties of embryonic stem (ES) cells make these cells very attractive in the field of replacement therapy, the molecular mechanisms involved in the maintenance of their pluripotency are not fully characterized. Starting from the observation that most pluripotent markers are also expressed by spermatogonia stem cells, we identified Tex19 as a new potential pluripotency marker. We show that Tex19 is a mammalian-specific protein duplicated in mouse and rat, renamed Tex19.1 and Tex19.2, whereas only one form is found in human. In mouse, both forms are localized on chromosome 11 and transcribed in opposite directions. Tex19 proteins are well conserved, showing two highly conserved domains that do not present any similarity with any other known domains. We show that Tex19.2 is specifically detected in the male somatic gonad lineage, whereas Tex19.1 expression is very similar to that of Oct4. Transcripts are maternally inherited, and expression starts as soon as the early embryo and later is limited to the germ line. Tex19.1 transcripts were also detected in mouse pluripotent stem cells, and expression of Tex19.1, like that of Oct4, decreases after murine embryonic stem and germ cell differentiation. Human TEX19 was more closely related to murine Tex19.1 and was also detected in adult testis and in undifferentiated ES cells. By immunofluorescence, we found that Tex19.1 protein localizes to the nucleus of mouse ES and inner cell mass cells. All these results suggest that Tex19.1, as well as human TEX19, could be a new factor involved in the maintenance of self-renewal or pluripotency of stem cells.
Disclosure of potential conflicts of interest is found at the end of this article.
Morphometrics ofManipora(Tabulata; Upper Ordovician; southern Manitoba, Canada)
Authors: Bae Boo-Young , Elias Robert J. , Lee Dong-Jin 
Published: December 2007

Multivariate morphometric analysis was applied for differentiation of closely related species and evaluation of intra- and interspecific variation inManiporafrom the Selkirk Member, Red River Formation, in southern Manitoba. Seven morphological characters were quantified in transverse thin sections of 46 coralla and statistically tested for selecting effective characters in discriminating species. Cluster analysis was performed on a raw data matrix coordinated with 46 coralla by three selected characters. Two major clusters on the resulting dendrogram were regarded as morphospecies, following comparative examination of the coralla using serial sections. Cluster analyses were also conducted on principal component score matrices obtained from the raw data set coordinated with 46 coralla by all seven characters, and from an experimental data set including the 46 coralla plus two replicates of each and six of the characters. the results agree closely with the first cluster analysis, but discrimination of morphospecies was slightly degraded. the validity of two morphospecies recognized in the first cluster analysis was verified by discriminant analyses, descriptive statistics, and bivariate plots. the results show that tabularium area is the most meaningful character for distinguishing these morphospecies; ranges of variations of the other six characters overlap between morphospecies.Another cluster analysis like the first was performed, but with the addition of 11 type specimens and reference coralla ofManiporaspecies from the Upper Ordovician of southern and northern Manitoba and Texas. Based on this analysis, together with comparative examination of thin sections, the two morphospecies are identified as valid species:M. amicarumSinclair, 1955 andM. manitoba(Sokolov, 1955).Manipora magnaFlower, 1961 is considered to be a synonym ofM. amicarum, whileM. trapezoidalisFlower, 1961 andM. garsonensisCaramanica, 1992 are considered to be synonyms ofM. manitoba, and the hypotypes ofM. amicarumof Nelson (1963) are assigned toM. manitoba.
A Screening Model for CO2 Flooding and Storage in Gulf Coast Reservoirs Based on Dimensionless Groups
Authors: Wood D. J. , Lake L. W. , Johns R. T. , Nunez V. 
Published: December 2007

Abstract
Concerns over global warming have led to interest in removing greenhouse gases, specifically CO2, from the atmosphere. Sequestration of CO2 in oil reservoirs as part of enhanced oil recovery (EOR) projects is one method being considered.
This paper first presents the scaling groups necessary to describe CO2 flooding for a typical line-drive pattern, and then uses these groups in a Box-Behnken experimental design to create a screening model most applicable to candidate Gulf Coast reservoirs. By generating oil recovery and CO2 storage curves, the model estimates the cumulative oil recovery and CO2 storage potential for a given reservoir. Past screening models – Rivas et al.1 and Diaz et al.2 – focused only on oil recovery and simply assigned qualitative rankings to reservoirs. Models that did include quantitative results, including CO2 Prophet3 and the CO2 Predictive Model4, did not include the effects of dip. This model focuses on both oil recovery and CO2 storage potential, produces quantitative results for each, and includes the effects of dip.
This model quickly estimates the oil recovery and CO2 storage potential for a reservoir. Operators alike can quickly screen large databases of reservoirs to identify the best candidates for CO2 flooding and storage. The scaling groups also provide the basis for future models that may be more specific to other regions.
The results show that continuous CO2 flooding can be fully described using ten dimensionless groups - aspect ratio, dip angle group, water and CO2 mobility ratios, buoyancy number, dimensionless injection and producing pressures, residual oil saturation to water and gas, and initial oil saturation. The effects of capillary forces and dispersion were secondary effects in this model and were not included in the scaling. Dimensionless oil recovery was effectively modeled with the dimensionless oil breakthrough time and the dimensionless recovery at three different dimensionless times, while CO2 storage potential was calculated only at the final dimensionless time. The reservoir-specific parameters discussed above were calculated from response surface fits. The scaling does not work as well at small buoyancy numbers; however, it is effective in the range of values typical of Gulf Coast reservoirs.
Sand Erosion in Weakly Consolidated Reservoirs: Experiments and Numerical Modeling
Authors: Servant G. , Marchina P. , Peysson Y. , Bemer E. , Nauroy J. -F. 
Published: December 2007

Abstract
Allowing sand to be produced is widely known to enhance oil production rates particularly for heavy-oils fields. However, in such a situation, it is very important to be able to determine the expected sand rate as well as the amount of sand produced during the life of the well.
To address this problem, an oedometric cell specially designed to simulate a radial flow towards a well has been developed at IFP. Tests performed under CT-scan on cohesionless sand samples allow to monitor in real time the initiation of the sand production and to follow the development of the sand producing zone.
In parallel, a numerical approach is proposed to simulate the dominant sanding mechanism. The theoretical model is based on the resolution of the equations of equilibrium at the interface between the intact zone and the slurry made of eroded sand and oil. An algorithm in 2-D was developed and implemented in a finite element code. Two calculations are alternatively performed: one on the intact zone (rock mass) and one on the slurry, respectively considered as a poroelastic medium and a Newtonian fluid. For each time step, it implies an iterative process to determine the unknown fluid pressure and solid displacements at the interface. The boundary between the slurry and the porous medium evolves as sand is produced. The problem to solve has then a geometry varying with time, but no a priori assumptions are made on the shape of the altered zone.
Modeling of the laboratory sand production experiments allows the ability of this model to reproduce the observed sand production mechanisms to be assessed. The influence on the results of numerical (temporal and geometrical discretization) parameters is also discussed.
An Experimental Study of Driving Mechanisms in MIOR Processes by Using Rhodococcus sp. 094
Authors: Crescente C. , Torsaeter O. , Hultmann L. , Stroem A. , Rasmussen K. , Kowalewski E. 
Published: December 2007

Abstract
Microbially Improved Oil Recovery with both a surfactant producing and a non surfactant producing variant of Rhodococcus sp 094 has been tested through coreflooding laboratory tests. A goniometer was also used to measure interfacial tension and wettability for the fluid systems involved in the corefloodings. Significant reductions of interfacial tension have been measured for both variants of the bacteria. Wettabilities also changed and bacterial systems were more oil wet than their brine counterpart. The effect of bacteria concentration on overall recovery also became apparent.
Feasibility Study of WAG Injection in Naturally Fractured Reservoirs
Authors: Heeremans J. C. , Esmaiel T. E. H. , Van Kruijsdijk C. P. J. W. 
Published: December 2007

Abstract
The fundamental aspects of Water Alternating Gas (WAG) injection are still not well understood. There are a few applications in fractured media and these show potential1. This study looks at the sensitivity of production to reservoir and fluid properties on a pattern scale using tools derived from experimental design. Also a look has been taken into the drive mechanisms in the fractured media that play an important role during WAG injection.
Earlier studies claimed that WAG injection in fractured reservoirs is not the best improved oil recovery (IOR) method2. However when the conditions are fully understood and the injection is modeled correctly, it is optimal in some fractured reservoirs. The proper modeling of fractured reservoirs remains difficult. The standard dual porosity formulation in commercial simulators is based on a continuous matrix grid overlaid by a continuous fracture grid. The transfer of fluid from matrix to fracture is described by a transfer function. The heart of this transfer function is the shape factor, sigma. As can be seen in a fine-scale grid, the shape factor is different for different reservoir properties and injection types. The upscaling of this sigma from the fine-scale grid to the pattern scale model is important for correct modeling. This study performs several fine scale single porosity simulations to properly upscale the flow model to a dual system.
The process of determining sensitivities in an organized manner on properly upscaled models will be shown here with a limited number of parameters. Fractured reservoirs can be divided into different categories3. Based on a fine grid model of one type of fractured media, a dual porosity model with varying parameters is set up. This yields recovery outputs across a range of reservoir properties that are represented by two dimensionless numbers. These numbers represent the capillary over viscous and gravity over viscous forces. By looking into the mechanisms that are behind the recovery in different balances of forces, an insight into when and why WAG is working is given.
Unconventional EOR Program Increases Recovery in Mature WAG Patterns at Prudhoe Bay
Authors: Rathmann M. P. , McGuire P. L. , Carlson B. H. 
Published: December 2007

Abstract
A large scale miscible water-alternating-gas (WAG) project was implemented in the Prudhoe Bay field in 1987. Many of the original patterns are no longer receiving miscible injectant (MI) due to pattern maturity and diminishing EOR response. The EOR project is being revived in the gravity-dominated eastern part of the Prudhoe Bay Field waterflood area, Flow Station 2 (FS2), by using horizontal sidetracks to place MI at various locations within existing conventional WAG patterns which have a significant remaining EOR target.
The sidetracks are completed at the toe and then perforated sequentially along the length of the horizontal wellbore to allow up to 7 independent points of miscible gas injection. Distributing the injection points enables MI to contact additional pore volume not contacted by the original WAG injector due to gravity segregation of the MI as it moves away from the injection wellbore.
Typical WAG benefits in this area range between 0.5 to 2 MMSTB. MIST injectors (MI Sidetracks) are recovering an additional 1.5 to 4.8 MMSTB in patterns that have already been WAG flooded. Typical MIST patterns accumulate 3 to 4 times the EOR reserves of conventional vertical well WAG patterns.
This paper will explain the reservoir characteristics that contribute to such large incremental recoveries. It will also cover well design and operational issues. Based upon the success of the initial MIST program, several additional MIST patterns have been drilled, and more are possible.
Formation and Propagation of Gel Aggregates Using Partially Hydrolyzed Polyacrylamide and Aluminum Citrate
Authors: Al-Assi A. A. , Willhite G. P. , Green D. W. , McCool C. S. 
Published: December 2007

AbstractA comprehensive study of the formation of gel aggregates in systems containing partially hydrolyzed polyacrylamide and aluminum citrate was completed. Under certain conditions, this system forms gel aggregates, commonly referred to as colloidal dispersion gels. Systems that formed aggregates on the exit screen of a screen viscometer also developed flow resistance when displaced through slim tubes and sand packs. A gel system containing 1000 ppm polymer and 33.3 ppm aluminum citrate was studied in sand packs 2ft and 4ft long. In the 2ft sandpack, the gelant showed no significant difference in the flow resistance when compared to polymer injection when 8.7 pore volumes were injected with at residence time 0.83 hours after mixing the gelant inline prior to injection. However, a high flow resistance developed after the sandpack was shut in for 31.4 hours. Viscosity measurements indicate that solution viscosity increases about 15 hours after mixing the solutions but a visible gel structure is not formed.In the 4ft sandpack, gelant was injected at a slow rate so that the residence time was 19.2 hours. A high flow resistance developed across the entire length of the sandpack demonstrating the formation and retention of gel aggregates in the sandpack. Our experimental data demonstrate that gel aggregates can be formed by reaction of partially hydrolyzed polyacrylamide with aluminum citrate and propagated through sandpacks. Permeability to brine following the gelant treatment was reduced by a factor of about 9000. In-depth treatment of a porous matrix by this process is limited because retention of gel aggregates causes the permeability to decrease leading to reduction in flowrate.