Increased expression of Interleukin-13 and connective tissue growth factor, and their potential roles during foreign body encapsulation of subcutaneous implantsW Kenneth Ward
Legacy Health System, 1225 NE 2nd Avenue, Portland, OR 97232, USA
J Biomater Sci Polym Ed 19:1065-72. 2008
....
- Controlled release of dexamethasone from subcutaneously-implanted biosensors in pigs: localized anti-inflammatory benefit without systemic effects
W Kenneth Ward
Legacy Health System, Portland, Oregon, USA
J Biomed Mater Res A 94:280-7. 2010
..c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010...
An implantable subcutaneous glucose sensor array in ketosis-prone rats: closed loop glycemic controlW Kenneth Ward
Legacy Clinical Research and Technology Center, Portland, OR 97232, USA
Artif Organs 29:131-43. 2005
..A revised algorithm yielded better glycemic control than the initial algorithm did. Future research needs to further improve calibration methods and reduce foreign body fibrosis in order to avoid a time-related increase in lag duration...
- The role of new technology in the early detection of hypoglycemia
W Kenneth Ward
Clinical Research and Technology Center, Legacy Health System, Portland, Oregon 97232, USA
Diabetes Technol Ther 6:115-7. 2004
Factors influencing the effectiveness of glucagon for preventing hypoglycemiaJessica R Castle
Oregon Health and Science University, Portland, Oregon 97239, USA
J Diabetes Sci Technol 4:1305-10. 2010
..Administration of small, intermittent doses of glucagon during closed-loop insulin delivery markedly reduces the frequency of hypoglycemia. However, in some cases, hypoglycemia occurs despite administration of glucagon in this setting...
- Continuous glucose monitoring in subjects with type 1 diabetes: improvement in accuracy by correcting for background current
Joseph El Youssef
Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
Diabetes Technol Ther 12:921-8. 2010
..We also tested whether increasing the frequency of sensor calibration would improve sensor accuracy...
- A controlled study of the effectiveness of an adaptive closed-loop algorithm to minimize corticosteroid-induced stress hyperglycemia in type 1 diabetes
Joseph El Youssef
Oregon Health and Science University, Portland, Oregon, USA
J Diabetes Sci Technol 5:1312-26. 2011
..6 ± 0.5%. We conclude that an adaptive algorithm that frequently estimates insulin sensitivity and adjusts gain factors is capable of minimizing corticosteroid-induced stress hyperglycemia...
- Development of a fully automated closed loop artificial pancreas control system with dual pump delivery of insulin and glucagon
Peter G Jacobs
Portland VA Medical Center and the Oregon Health and Sciences University, Portland, OR 97239, USA
Conf Proc IEEE Eng Med Biol Soc 2011:397-400. 2011
..Results from this work may ultimately lead to development of a portable, easy to use, artificial pancreas device that can enable far better glycemic control in patients with diabetes...
- Amperometric glucose sensors: sources of error and potential benefit of redundancy
Jessica R Castle
Oregon Health Services University, Portland, Oregon, USA
J Diabetes Sci Technol 4:221-5. 2010
..If an array with three or more sensors were available, it would likely allow even better accuracy with the use of voting...
- A novel insulin delivery algorithm in rats with type 1 diabetes: the fading memory proportional-derivative method
Bala Gopakumaran
Legacy Clinical Research and Technology Center, Portland, OR 97232, USA
Artif Organs 29:599-607. 2005
..0 vs. 130 +/- 2.9 mg/dL). Neither version produced hypoglycemia. Future research using this algorithm needs to focus on automated glucose sensing in combination with insulin delivery...
- Safe glycemic management during closed-loop treatment of type 1 diabetes: the role of glucagon, use of multiple sensors, and compensation for stress hyperglycemia
W Kenneth Ward
Oregon Health and Science University, Portland, Oregon 97239, USA
J Diabetes Sci Technol 5:1373-80. 2011
..Elements such as the use of glucagon to minimize hypoglycemia, adaptation to changes in insulin sensitivity, and sensor redundancy will likely increase safety during outpatient use of closed-loop glycemic control systems...
- The accuracy benefit of multiple amperometric glucose sensors in people with type 1 diabetes
Jessica R Castle
Department of Medicine, Division of Endocrinology, Diabetes and Clinical Nutrition, Oregon Health and Science University, Portland, Oregon, USA
Diabetes Care 35:706-10. 2012
..To improve glucose sensor accuracy in subjects with type 1 diabetes by using multiple sensors and to assess whether the benefit of redundancy is affected by intersensor distance...
- Elevation of transforming growth factor beta (TGFbeta) and its downstream mediators in subcutaneous foreign body capsule tissue
Allen G Li
Department of Dermatology, Oregon Health and Science University, Portland, Oregon 97239, USA
J Biomed Mater Res A 82:498-508. 2007
..We suggest that TGFbeta plays an important role in the FBC formation. Inhibition of TGFbeta signaling could be a promising strategy in the prevention of FBC formation, thereby extending the useful life of subcutaneous implants...
- The effect of local subcutaneous delivery of vascular endothelial growth factor on the function of a chronically implanted amperometric glucose sensor
W Kenneth Ward
Clinical Research and Technology Center, Legacy Health System, Portland, Oregon 97232
Diabetes Technol Ther 6:137-45. 2004
..Slow release of angiogenic growth factors may be a potential method for chronically enhancing the function of a subcutaneously implanted biosensor...
- A fully implantable subcutaneous glucose sensor array: enhanced accuracy from multiple sensing units and a median-based algorithm
W Kenneth Ward
Legacy Clinical Research and Technology Center, Legacy Health System, Portland, Oregon 97232, USA
Diabetes Technol Ther 5:943-52. 2003
..When tested in an implanted array of glucose sensors, a median-based technique (ZMAD) yields an accurate unified signal, and its accuracy is superior to signal averaging...
- Induction of type-1 diabetes mellitus in laboratory rats by use of alloxan: route of administration, pitfalls, and insulin treatment
Isaac F Federiuk
Legacy Clinical Research and Technology Center, 1225 NE 2nd Avenue, Portland, Oregon 97232, USA
Comp Med 54:252-7. 2004
..If specific precautions are observed, intraperitoneal administration of high-dose alloxan to laboratory rats leads to a condition that closely resembles human type-1 DM...
- Vascularizing the tissue surrounding a model biosensor: how localized is the effect of a subcutaneous infusion of vascular endothelial growth factor (VEGF)?
W Kenneth Ward
Legacy Health System, Legacy Clinical Research and Technology Center, 1225 NE 2nd Avenue, Portland, OR 97232, USA
Biosens Bioelectron 19:155-63. 2003
..Vascularization of a foreign body capsule surrounding a subcutaneous biosensor might well extend its useful life...
- Stable liquid glucagon formulations for rescue treatment and bi-hormonal closed-loop pancreas
Melanie A Jackson
Oregon Health and Science University OHSU, 3181 SW Sam Jackson Park Road, OP05DC, Portland, OR 97239, USA
Curr Diab Rep 12:705-10. 2012
..Assays for cyclic AMP (cAMP) or its downstream effector, protein kinase A (PKA), in engineered cell systems, are more reliable and suitable for inexpensive, high-throughput assessment of bioactivity...
- Novel use of glucagon in a closed-loop system for prevention of hypoglycemia in type 1 diabetes
Jessica R Castle
Department of Medicine, Division of Endocrinology, Oregon Health and Science University, Portland, Oregon, USA
Diabetes Care 33:1282-7. 2010
..To minimize hypoglycemia in subjects with type 1 diabetes by automated glucagon delivery in a closed-loop insulin delivery system...
- In vitro and in vivo evaluation of native glucagon and glucagon analog (MAR-D28) during aging: lack of cytotoxicity and preservation of hyperglycemic effect
W Kenneth Ward
Legacy Health System Research, Portland, Oregon 97232, USA
J Diabetes Sci Technol 4:1311-21. 2010
..However, under some conditions, solutions of glucagon can form amyloid fibrils. Currently, the usage instructions for commercially available glucagon allow only for its immediate use...
- Discomfort from an alkaline formulation delivered subcutaneously in humans: albumin at pH 7 versus pH 10
W Kenneth Ward
Legacy Health and Legacy Research Institute, Portland, OR, USA
Clin Drug Investig 32:433-8. 2012
..There is a paucity of data regarding tolerability of alkaline drugs administered subcutaneously. The aim of this study was to assess the tolerability of alkaline preparations of human albumin delivered subcutaneously to healthy humans...
- A wire-based dual-analyte sensor for glucose and lactate: in vitro and in vivo evaluation
W Kenneth Ward
iSense Corporation, Portland, Oregon 97224, USA
Diabetes Technol Ther 6:389-401. 2004
..This study constitutes proof of the concept that oxidase-based, amperometric wire microsensors can detect changes in glucose and lactate during subcutaneous implantation in rats...
- The effect of microgeometry, implant thickness and polyurethane chemistry on the foreign body response to subcutaneous implants
W Kenneth Ward
Legacy Clinical Research and Technology Center, 1225 NE 2nd Ave, Portland, OR 97232, USA
Biomaterials 23:4185-92. 2002
..In addition, thin implants lead to a thin FBC. Porous implants (PVA and ePTFE) cause more angiogenesis than solid implants. These results may have implications for the measurement of blood-derived analytes by biosensors...
- A new amperometric glucose microsensor: in vitro and short-term in vivo evaluation
W Kenneth Ward
iSense Corporation, 16125 SW 72nd Avenue, Portland, OR 97224, USA
Biosens Bioelectron 17:181-9. 2002
..The response of the revised protocol sensors (n=7) to intraperitoneal glucose was tested in rats approximately one day after subcutaneous implantation and the sensors tracked glucose closely with a slight lag of 3-6 min...
- Passivating protein coatings for implantable glucose sensors: evaluation of protein retention
Steven J Geelhood
Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, USA
J Biomed Mater Res B Appl Biomater 81:251-60. 2007
..Preadsorbed proteins on polymers appear to be removed by passive exchange and/or displacement by plasma proteins and by proteases released by monocytes...
- Prevention of hypoglycemia using risk assessment with a continuous glucose monitoring system
Carine Choleau
INSERM U341, Diabetes Department, , Paris, France
Diabetes 51:3263-73. 2002
..This was, of course, not the case when the same glucose load was infused at the detection of the hypoglycemia threshold...
