Simultaneous Estimation of Relative Permeability and Porosity/Permeability Fields by History Matching Production Data

Abstract

This paper presents a procedure to estimate relative permeability curves together with gridblock porosities and permeabilities by automatic history matching three-phase flow production data using the LBFGS algorithm for optimization and the adjoint method for generating sensitivity coefficients. Both power law and B-splines are considered for the representation of relative permeability curves. Power law functions provide a simple representation; however, B-splines have the advantage of being able to accurately represent any set of relative permeability curves. In the B-spline representation, we provide a simple procedure based on a transformation of parameters (control points) defining the B-splines to ensure that monotonic curves are obtained. Without this transformation, the automatic history-matching process fails. If endpoint saturations are included as parameters, we show how to modify the adjoint procedure to account for the fact that initial conditions are sensitive to endpoint saturations. While the history-matching process is inherently non-unique, we show that reasonable estimates of relative permeability curves and porosity/ permeability fields can be obtained for a synthetic reservoir example. We also provide a quantification of the uncertainty in model parameters and reservoir performance prediction using the randomized maximum likelihood (RML) method.

Introduction

Usually, the relative permeability curves are obtained from labs through coreflood tests. However, they can also be incorporated into the history matching procedure as model parameters. Archer and Wong(1) and Yang and Watson(2) were among the early researchers to consider the estimation of relative permeability curves by history matching laboratory coreflood data. A detailed literature review is given in Reynolds et al.(3). Reynolds et al.(3) also discussed the estimation of three-phase relative permeabilities by history matching production data.

The current work is a natural extension of Reynolds et al.(3). In this paper, we provide an alternative method for relative permeability estimation based on B-spline approximation. Compared to power law representation, B-splines have the advantage of being able to accurately represent any set of relative permeability curves.

Bacterial and archaeal assemblages in sediments of a large shallow freshwater lake, Lake Taihu, as revealed by denaturing gradient gel electrophoresis

AIMS

To explore the association of microbial community structure with the development of eutrophication in a large shallow freshwater lake, Lake Taihu.

METHODS AND RESULTS

The bacterial and archaeal assemblages in sediments of different lake areas were analysed using denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA fragments. The bacterial DGGE profiles showed that eutrophied sites, grass-bottom areas and relatively clean sites with a eutrophic (albeit dredged) site are three respective clusters. Fifty-one dominant bacterial DGGE bands were detected and 92 corresponding clones were sequenced, most of which were affiliated with bacterial phylotypes commonly found in freshwater ecosystems. Actinobacteria were detected in the centre of the lake and not at eutrophied sites whereas the opposite was found with respect to Verrucomicrobiales. Twenty-five dominant archaeal DGGE bands were detected and 31 corresponding clones were sequenced, most of which were affiliated with freshwater archaeal phylotypes.

CONCLUSIONS

The bacterial community structures in the sediments of different areas with similar water quality and situation tend to be similar in Taihu Lake.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study may expand our knowledge on the relationship between the overall microbial assemblages and the development of eutrophication in the shallow freshwater lake.

A subject-specific technique for respiratory motion correction in image-guided cardiac catheterisation procedures

We describe a system for respiratory motion correction of MRI-derived roadmaps for use in X-ray guided cardiac catheterisation procedures. The technique uses a subject-specific affine motion model that is quickly constructed from a short pre-procedure MRI scan. We test a dynamic MRI sequence that acquires a small number of high resolution slices, rather than a single low resolution volume. Additionally, we use prior knowledge of the nature of cardiac respiratory motion by constraining the model to use only the dominant modes of motion. During the procedure the motion of the diaphragm is tracked in X-ray fluoroscopy images, allowing the roadmap to be updated using the motion model. X-ray image acquisition is cardiac gated. Validation is performed on four volunteer datasets and three patient datasets. The accuracy of the model in 3D was within 5mm in 97.6% of volunteer validations. For the patients, 2D accuracy was improved from 5 to 13mm before applying the model to 2-4mm afterwards. For the dynamic MRI sequence comparison, the highest errors were found when using the low resolution volume sequence with an unconstrained model.

Effects of denosumab treatment in breast cancer patients with bone metastases and elevated bone resorption levels after therapy with intravenous bisphosphonates: results of a phase 2 randomized trial

Abstract #1155

Background: Patients with breast cancer-induced bone disease and elevated urine-N-telopeptide (uNTx), a marker of bone resorption, are at increased risk for skeletal complications, disease progression, and death. Receptor activator of NF-kB ligand (RANKL) mediates osteoclastic bone resorption. Denosumab, a fully human monoclonal antibody, inhibits bone destruction by binding and neutralizing RANKL. Denosumab efficacy and safety were assessed in a phase 2, randomized, open-label, active-controlled trial in patients with bone metastases and elevated levels of uNTx after at least 8 weeks of intravenous (IV) bisphosphonate (BP) therapy. We report results in a subset of patients with breast cancer.
 Methods: Cancer patients with bone metastases and uNTx >50 nM/mM creatinine [Cr] following at least 8 weeks of IV BP therapy were randomized to continue IV BP therapy every 4 weeks (Q4W) or switch to subcutaneous (SC) denosumab injection (180 mg) Q4W or every 12 weeks (Q12W). The primary endpoint was the proportion of patients who achieved uNTx <50 nM/mM at week 13. Safety was also assessed.
 Results: The study population (N = 111) included 46 patients (41%) with breast cancer; the median time since diagnosis of bone metastases was approximately 1 year in both groups. At week 13, 76% of denosumab-treated patients and 33% of IV BP-treated patients had uNTx < 50 nM/mM. Denosumab-induced suppression of uNTx was rapid (as early as 2 weeks after initial treatment), sustained through week 25, and unaffected by baseline uNTx (Table). In the total study population, adverse events of grade 3, 4, or 5 were reported in 25 (71%) IV BP-treated patients and 40 (55%) denosumab-treated patients.
 
 Discussion: Denosumab reduced bone turnover in breast cancer patients with bone metastases and elevated uNTx despite prior IV BP therapy. Phase 3 trials of denosumab in cancer patients with bone metastases are in progress.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1155.

Deterministic Dynamics in Neuronal Discharge from Pallidotomy Targets

The non-linear dynamic specificity of the firing pattern discharged from neurons of the internal globus pallidus (GPi) was investigated by recording their spontaneous firing using a microelectrode during posteroventral pallidotomy in eight patients with Parkinson's disease. Raw data from the cells were processed to extract spiking events (discharges above a selected threshold) and the interspike interval was measured. Using the unstable periodic orbits extraction method, significant period-1, −2 and −3 orbits were identified in burst firing discharged from the GPi cells in all eight patients, suggesting that deterministic dynamics exist in the timing of the discharges. As well as providing a useful peri-operative technique for locating posteroventral pallidotomy targets in Parkinson's disease, this method also provides a promising basis for investigating characteristic neuronal discharges in other regions of the brain and for various other neurological disorders.

The Nucleus Accumbens Core has a More Important Role in Resisting Reactivation of Extinguished Conditioned Place Preference in Morphine-addicted Rats

We investigated the roles of the core and shell subfields of the nucleus accumbens (NAc) in drug- or foot-shock-induced reactivation of extinguished conditioned place preference (CPP) in morphine-addicted rats. Rats were given electrolytic lesions to either the core or shell after CPP was established. After surgery, a reduction of CPP scores to morphine was observed in all groups. During the reacquisition of morphine-seeking behaviour, rats in the shell and sham lesion groups regained their CPP, while the CPP in core lesion rats remained severely impaired. Similarly, foot-shock-induced reactivation of CPP in the core lesion group was significantly lower than that of the shell and sham lesion groups, and there was no significant difference between these latter groups. Our results demonstrate that NAc core and shell lesions elicited dissociable effects on reactivation of extinguished CPP in rats, suggesting that the NAc core might play a more important role in resisting reactivation of extinguished CPP in morphine-addicted rats.

Nicotinamide adenine dinucleotide based therapeutics

Nicotinamide adenine dinucleotide (NAD), generally considered a key component involved in redox reactions, has been found to participate in an increasingly diverse range of cellular processes, including signal transduction, DNA repair, and post-translational protein modifications. In recent years, medicinal chemists have become interested in the therapeutic potential of molecules affecting interactions of NAD with NAD-dependent enzymes. Also, enzymes involved in de novo biosynthesis, salvage pathways, and down-stream utilization of NAD have been extensively investigated and implicated in a wide variety of diseases. These studies have bolstered NAD-based therapeutics as a new avenue for the discovery and development of novel treatments for medical conditions ranging from cancer to aging. Industrial and academic groups have produced structurally diverse molecules which target NAD metabolic pathways, with some candidates advancing into clinical trials. However, further intensive structural, biological, and medical studies are needed to facilitate the design and evaluation of new generations of NAD-based therapeutics. At this time, the field of NAD-therapeutics is most likely at a stage similar to that of the early successful development of protein kinase inhibitors, where analogs of ATP (a more widely utilized metabolite than NAD) began to show selectivity against target enzymes. This review focuses on key representative opportunities for research in this area, which extends beyond the scope of this article.

Predictors of outcome and treatment decisions of older patients with stage III non-small cell lung cancer

19574

Background: In treating Stage III non-small cell lung cancer in the elderly, oncologists often empirically adjust treatment without clear guidelines. Identifying patient characteristics that impact prognosis will aid in creating better treatment algorithms in this patient population. Methods: A retrospective analysis was done on older patients (age > 70) treated for Stage III NSCLC (excluding “wet” IIIB) at the H. Lee Moffitt Cancer. Cox multivariate analysis identified variables impacting progression free survival, overall survival, treatment chosen, treatment interruptions, and hospitalizations. Correlation and regression tree analysis (CART) was performed to create potential decision making models. Results: 213 patients were evaluable. Multivariate analysis identified ECOG performance status (hazard ratio = 1.52, p = 0.005) and nodal status (HR = 1.36, p = 0.001) as negatively associated with PFS while BMI (HR = 0.96, p = 0.02) was positively associated. ECOG performance status (HR = 2.26, p < 0.0001), nodal status (HR = 1.18, p = 0.08), and CIRS3 (having a comorbidity classified as severity 3; HR = 1.33, p = 0.02) were negatively associated with OS. BMI (HR = 0.95, p = 0.002) and CIRSmean (mean CIRS-G severity score; HR 0.61, p = 0.01) were positively associated with OS. These variables were also identified as the most significant splitters, along with smoking status and pulmonary function, in CART analyses. Trees using PFS and OS as outcomes were created with receiver operating curves (ROC) ranging from 0.64–0.75. A CART analysis targeting treatment modality chosen had ROCs ranging from 0.49–0.78. Conclusions: Our multivariate analysis found ECOG performance status, nodal status, and severe medical comorbidity as negatively associated with survival. Unexpectedly, BMI (at initial treatment), independent of weight loss, was found to be positively associated. Also, the splitter variables identified by CART analysis were very similar to the general multivariate model, but the weights differed in the various analyses and subgroups of patients. The CART analyses suggest that we can create decision making models with a range of applicability comparable to those commonly considered useful for clinical guidelines, i.e. about 60% of straightforward application.

No significant financial relationships to disclose.

Periprocedural complications associated with endovascular embolisation of intracranial ruptured aneurysms with matrix coils

INTRODUCTION

Matrix is a type of bioactive coil expected to produce healing of cerebral aneurysms. We reviewed periprocedural complications associated with endovascular embolisation of ruptured intracranial aneurysms with matrix coils and evaluated the effects of matrix coils.

METHODS

From October 2003 to September 2005, a total of 102 patients with 102 ruptured aneurysms and ten unruptured aneurysms underwent embolisations with matrix coils. We reviewed the medical records, radiographical studies and endovascular procedures to evaluate the morbidity and mortality related to ruptured aneurysm coiling.

RESULTS

16 complications (15.7 percent) occurred, of which 14 were in the anterior circulation and two in the posterior circulation. Complications included nine intraprocedural ruptures (8.8 percent), three thromboembolism (2.9 percent), one coil migration (1.0 percent) and three parent vessel occlusions (2.9 percent). Six complications had no neurological consequences, three were with transient deficits, six resulted in persistent neurological deficits, and one caused the patient to die. No complication was associated with balloon remodelling technique, and coil migration occurred during one of the neuroform-assisted embolisations. Procedural-related neurological morbidity and mortality for all 102 embolisations of ruptured aneurysms were 5.9 percent and 1.0 percent, respectively.

CONCLUSION

Endovascular treatment of ruptured intracranial aneurysms with matrix coils is as safe as with bare platinum coils. Matrix coil does not increase the risk of thromboembolism. However, we must be cautious when we embolise small aneurysms with matrix coils, especially when the aneurysms are less than 5 mm in diameter.

Multifunctional role of choline binding protein G in pneumococcal pathogenesis

Members of the choline binding protein (Cbp) family are noncovalently bound to phosphorylcholine residues on the surface of Streptococcus pneumoniae. It has been suggested that CbpG plays a role in adherence and increase virulence both at the mucosal surface and in the bloodstream, but the function of this protein has been unclear. A new sequence analysis indicated that CbpG is a possible member of the S1 family of multifunctional surface-associated serine proteases. Clinical isolates contained two alleles of cbpG, and one-third of the strains expressed a truncated protein lacking the C-terminal, cell wall-anchoring choline binding domain. CbpG on the surface of pneumococci (full length) or released into the supernatant (truncated) showed proteolytic activity for fibronectin and casein, as did CbpG expressed on lactobacilli or as a purified full-length or truncated recombinant protein. Recombinant CbpG (rCbpG)-coated beads adhered to eukaryotic cells, and TIGR4 mutants lacking CbpG or having a truncated CbpG protein showed decreased adherence in vitro and attenuation of disease in mouse challenge models of colonization, pneumonia, and bacteremia. Immunization with rCbpG was protective in an animal model of colonization and sepsis. We propose that CbpG is a multifunctional surface protein that in the cell-attached or secreted form cleaves host extracellular matrix and in the cell-attached form participates in bacterial adherence. This is the first example of distinct functions in virulence that are dependent on natural variation in expression of a choline binding domain.

Analysis of ADAMTS4 and MT4-MMP indicates that both are involved in aggrecanolysis in interleukin-1-treated bovine cartilage

OBJECTIVE

To investigate the mechanism of aggrecanolysis in interleukin-1 (IL-1)-treated cartilage tissue by examining the time course of aggrecan cleavages and the tissue and medium content of membrane type 4-matrix metalloproteinases (MT4-MMP) and a disintegrin and metalloproteinase with thrombospondin type I motifs (ADAMTS)4.

METHODS

Articular cartilage explants were harvested from newborn bovine femoropatellar groove. The effects of IL-1 treatment with or without aggrecanase blockade were investigated by Western analysis of aggrecan fragment generation, ADAMTS4 species (p68 and p53), and MT4-MMP, as well as by realtime PCR (polymerase chain reaction) for ADAMTS4 and 5. Aggrecanase was blocked with mannosamine (ManN), an inhibitor of glycosylphosphatidylinositol anchor synthesis, and esculetin (EST), an inhibitor of MMP-1, MMP-3, and MMP-13 gene expression.

RESULTS

IL-1 treatment caused a major increase in MT4-MMP abundance in the tissue and medium. ADAMTS4 (p68) was abundant in fresh cartilage and this was retained in the tissue in untreated cartilage. IL-1 treatment for 6 days caused a marked loss of p68 from the cartilage and the appearance of p53 in the medium. Addition of either 1.35 mM ManN or 31-500 microM EST blocked IL-1-mediated aggrecanolysis and this was accompanied by nearly complete inhibition of the MT4-MMP increase, the p68 loss and the formation of p53. IL-1 treatment increased mRNA abundance for ADAMTS4 ( approximately 3-fold) and ADAMTS5 ( approximately 10-fold) but this was not accompanied by a marked change in enzyme protein abundance.

CONCLUSION

These studies support a central role for MT4-MMP in IL-1-induced cartilage aggrecanolysis and are consistent with the identification of p68 as the aggrecanase that cleaves within the CS2 domain, and of p53 as the aggrecanase that generates G1-NITEGE. Since the induction by IL-1 was not accompanied by marked changes in total ADAMTS4 protein, but rather in partial conversion of p68 to p53 and release of both from the tissue, we conclude that aggrecanolysis in this model system results from MT4-MMP-mediated processing of a resident pool of ADAMTS4 and release of the p68 and p53 from their normal association with the cell surface.

Evaluation of toxicity from high-dose systemic administration of recombinant adenovirus vector in vector-naïve and pre-immunized mice

Toxicity associated with in vivo administration of adenovirus (Ad) vectors has been linked to activation of both innate and adaptive immune responses. Pre-existing immunity to the prevalent Ad serotypes, acquired by the majority of the human population as a result of natural infections, has the potential to modulate vector efficacy and safety. Previously, we evaluated some aspects of toxicity from systemic Ad vector in vector-naive and pre-immunized rhesus monkeys. In this report, we summarize data from several studies analyzing toxic effects from systemically administered E1/E3-deleted Ad vector in vector-naive and pre-immunized C57BL/6 mice. Our results indicate that pre-immunization can be associated with increased mortality shortly after systemic administration of Ad. Transient leukopenia and thrombocytopenia were observed early post vector infusion in both vector-naive and pre-immunized animals. Pre-exposure to the vector did not prevent induction of pro-inflammatory cytokines; however, pre-immunized mice showed less tissue toxicity. Growth of bone marrow myeloid and erythroid progenitors was transiently inhibited in pre-immunized animals, but only the myeloid progenitors were affected in vector-naive animals. In summary, pre-existing immunity to Ad vector substantially modifies host immune responses to systemic Ad vector.

The minimum number of clones necessary to sequence in order to obtain the maximum information about hepatitis C virus quasispecies: a comparison of subjects with and without liver cancer

Most studies of hepatitis C virus (HCV) quasispecies have reported the results of sequencing only three to five clones per sample. The possibility that sequencing so few clones might not provide a representative picture of the quasispecies present in a sample has never been evaluated. The present study was conducted to evaluate whether sequencing greater numbers of clones results in better information about the HCV quasispecies number and distribution, and to compare the HCV quasispecies in liver cancer cases and controls. RNA was extracted from serial serum samples from six subjects with HCV-associated liver cancer and 11 age- and sex-matched HCV-infected controls without liver cancer. The hypervariable region 1 (HVR1) of the HCV genome was amplified, cloned, and sequenced. For further studies of 12 serum samples from two liver cancer cases and two matched controls, successive groups of 10 additional clones were sequenced up to a total of 50 clones per serum sample. When only 10 clones were sequenced from each specimen, no consistent differences were seen between the number of HCV quasispecies in the six liver cancer cases and the 11 controls. However, sequencing 40 clones from each of 12 samples from two liver cancer cases and two controls revealed a greater number of quasispecies in liver cancer cases than in controls. Testing an additional 10 clones (50 clones per sample) did not significantly increase the number of quasispecies detected.

Plasminogen kringle 5 reduces vascular leakage in the retina in rat models of oxygen-induced retinopathy and diabetes

AIMS/HYPOTHESIS

Retinal vascular leakage is an early pathological feature in diabetic retinopathy and can lead to macular oedema and loss of vision. Previously we have shown that plasminogen kringle 5 (K5), an angiogenic inhibitor, inhibits retinal neovascularisation in the rat model of oxygen-induced retinopathy (OIR). The purpose of this study was to examine the effect of K5 on vascular leakage in the retina.

METHODS

Neonatal rats were exposed to hyperoxia to induce OIR. Diabetes was induced in adult rats by injecting streptozotocin. Vascular permeability was measured by Evans blue method. Expression of vascular endothelial growth factor (VEGF) was evaluated using immunohistochemistry and western blot analysis.

RESULTS

Rats with OIR and diabetes showed abnormal vascular hyperpermeability in the retina and iris. Intravitreal injection of K5, reduced vascular permeability in both animal models, but did not affect permeability in normal rats. K5 reduced vascular permeability at doses substantially lower than that required for inhibition of retinal neovascularisation. The K5-induced reduction in vascular permeability correlated with its down-regulation of VEGF expression in the retina. Moreover, K5 inhibited IGF-1-induced hyperpermeability, which is known to arise through up-regulation of endogenous VEGF expression. However, K5 had no effect on the hyperpermeability induced by injection of exogenous VEGF.

CONCLUSIONS/INTERPRETATION

Very low doses of K5 reduce pathological vascular leakage in the retina. K5 thus has therapeutic potential in the treatment of diabetic macular oedema. This effect can be ascribed, at least in part, to the down-regulation of endogenous VEGF expression.

High throughput creation of recombinant adenovirus vectors by direct cloning, green-white selection and I-Sce I-mediated rescue of circular adenovirus plasmids in 293 cells

Ability of replication-defective adenovirus vectors to achieve efficient gene transfer in most of the mammalian cell types makes them useful vehicles for many gene transfer applications, including their use in assessing gene function. High throughput creation of recombinant adenovirus becomes a critical path to the expanding utility of adenovirus vector technology. Here, we report a process in which recombinant adenovirus vectors are isolated as single molecular clones through a convenient direct cloning and green-white selection procedure, and directly transfected into 293 cells where virus is rescued through an enzymatic reaction mediated by an intron-encoding rare endonuclease I-Sce I. This process of enzymatic rescue of circular molecular clones was at least 10-fold more efficient than that using linearized clones for transfection. This method will facilitate a high throughput creation of vectors as required for screening gene function.