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1.  Comparison of thermal coagulation profiles for bipolar forceps with different cooling mechanisms in a porcine model of spinal surgery 
Coagulation accomplished using bipolar forceps is common in neurosurgery. Control of thermal spread from the forceps tips into surrounding neural tissues is a persistent concern, as neural tissues are especially vulnerable to heat injury. The purpose of our investigation was to compare the efficacy of cooling mechanisms for four different bipolar forceps and to understand thermal spread when coagulating vessels on the spinal cord.
Immediately following euthanasia, the dura mater of an ex vivo porcine model was opened to expose vessels on the spinal cord for coagulation. Temperature profiles were measured at generator power of 25 W and at fixed 5-second activation times. The bipolar forceps used in this study included regular stainless steel, titanium, heat-pipe embedded, and SILVERGlide forceps. Temperature was measured by micro-thermistor at the midpoint between the bipolar tips, and 1 and 2 mm away from the midpoint along the centerline. Statistical analysis was performed to evaluate temperature differences.
Temperature profiles indicated that heat-pipe embedded forceps create the least amount of temperature increase and the highest normalized temperature decreasing slope after activation. The decreasing slope of SILVERGlide forceps is slightly higher than that of regular stainless steel forceps.
Bipolar forceps incorporating either heat-pipe embedded technology or SILVERGlide coating can effectively limit excessive thermal spread, thus decreasing potential injury to adjacent tissues when compared with standard stainless steel and titanium bipolar forceps. Of the two, heat-pipe embedded technology appeared safest, having better cooling efficiency at higher temperature.
PMCID: PMC3779387  PMID: 24083049
Bipolar; spinal cord; spine surgery; thermal injury
2.  The efficacy and safety of the dipeptidyl peptidase-4 inhibitor saxagliptin in treatment-naïve patients with type 2 diabetes mellitus: a randomized controlled trial 
The aim of this study was to assess efficacy and safety of saxagliptin monotherapy for up to 76 weeks in patients with type 2 diabetes mellitus (T2DM) and inadequate glycemic control, with main efficacy assessment at 24 weeks.
365 treatment-naïve patients with T2DM (HbA1c 7.0%–10.0%) were treated with saxagliptin 2.5 mg q.A.M., saxagliptin 2.5 mg q.A.M. with possible titration to saxagliptin 5 mg, saxagliptin 5 mg q.A.M., saxagliptin 5 mg q.P.M., or placebo. After week 24, patients in all groups were eligible for titration to saxagliptin 10 mg based on HbA1c ≥7%, and all unrescued placebo patients began blinded metformin 500 mg/day. Rescue with open-label metformin was available for patients with inadequate glycemic control.
At week 24, placebo-subtracted mean HbA1c reduction from baseline (LOCF) was significantly greater in the saxagliptin treatment groups vs placebo, and remained greater through week 76. Serious adverse events (AEs) and discontinuations due to AEs were similar in saxagliptin and control groups; incidence of confirmed hypoglycemia was low across all treatment groups (saxagliptin-treated, 2 [0.7]; control, 1 [1.4]).
In treatment-naïve patients with T2DM, saxagliptin monotherapy demonstrated statistically significant improvement in HbA1c compared with placebo at 24 weeks and was generally well tolerated for up to 76 weeks.
Trial registration Identifier: NCT00316082
PMCID: PMC3541110  PMID: 22828124
DPP-4 inhibitor; Monotherapy; Saxagliptin; Titration; Type 2 diabetes mellitus
3.  The Efficacy and Safety of Saxagliptin When Added to Metformin Therapy in Patients With Inadequately Controlled Type 2 Diabetes With Metformin Alone 
Diabetes Care  2009;32(9):1649-1655.
This 24-week trial assessed the efficacy and safety of saxagliptin as add-on therapy in patients with type 2 diabetes with inadequate glycemic control with metformin alone.
This was a randomized, double-blind, placebo-controlled study of saxagliptin (2.5, 5, or 10 mg once daily) or placebo plus a stable dose of metformin (1,500–2,500 mg) in 743 patients (A1C ≥7.0 and ≤10.0%). Efficacy analyses were performed using an ANCOVA model using last observation carried forward methodology on primary (A1C) and secondary (fasting plasma glucose [FPG] and postprandial glucose [PPG] area under the curve [AUC]) end points.
Saxagliptin (2.5, 5, and 10 mg) plus metformin demonstrated statistically significant adjusted mean decreases from baseline to week 24 versus placebo in A1C (−0.59, −0.69, and −0.58 vs. +0.13%; all P < 0.0001), FPG (−14.31, −22.03, and −20.50 vs. +1.24 mg/dl; all P < 0.0001), and PPG AUC (−8,891, −9,586, and −8,137 vs. −3,291 mg · min/dl; all P < 0.0001). More than twice as many patients achieved A1C <7.0% with 2.5, 5, and 10 mg saxagliptin versus placebo (37, 44, and 44 vs. 17%; all P < 0.0001). β-Cell function and postprandial C-peptide, insulin, and glucagon AUCs improved in all saxagliptin treatment groups at week 24. Incidence of hypoglycemic adverse events and weight reductions were similar to those with placebo.
Saxagliptin once daily added to metformin therapy was generally well tolerated and led to statistically significant improvements in glycemic indexes versus placebo added to metformin in patients with type 2 diabetes inadequately controlled with metformin alone.
PMCID: PMC2732156  PMID: 19478198
4.  Hypertension Knowledge, Awareness, and Attitudes in a Hypertensive Population 
Improved recognition of the importance of systolic blood pressure (SBP) has been identified as one of the major public health and medical challenges in the prevention and treatment of hypertension (HTN). SBP is a strong independent risk factor for cardiovascular disease but no information is available on whether patients understand the importance of their SBP level. The purpose of this study was to assess HTN knowledge, awareness, and attitudes, especially related to SBP in a hypertensive population.
We identified patients with HTN (N =2,264) in the primary care setting of a large midwestern health system using automated claims data (International Classification of Diseases, Ninth Revision [ICD-9] codes 401.0–401.9). We randomly selected 1,250 patients and, after excluding ineligible patients, report the results on 826 completed patient telephone interviews (72% response rate [826/1,151]).
Ninety percent of hypertensive patients knew that lowering blood pressure (BP) would improve health and 91% reported that a health care provider had told them that they have HTN or high BP. However, 41% of patients did not know their BP level. Eighty-two percent of all patients correctly identified the meaning of HTN as “high blood pressure.” Thirty-four percent of patients correctly identified SBP as the “top” number of their reading; 32% correctly identified diastolic blood pressure (DBP) as the “bottom” number; and, overall, only 30% of patients were able to correctly identify both systolic and diastolic BP measures. Twenty-seven percent of patients with elevated SBP and DBP (as indicated by their medical records) perceived that their BP was high. Twenty-four percent of patients did not know the optimal level for either SBP or DBP. When asked whether the DBP or SBP level was more important in the control and prevention of disease, 41% reported DBP, 13% reported SBP, 30% reported that both were important, and 17% did not know.
These results suggest that, although general knowledge and awareness of HTN is adequate, patients do not have a comprehensive understanding of this condition. For instance, patients do not recognize the importance of elevated SBP levels or the current status of their BP control. An opportunity exists to focus patient education programs and interventions on the cardiovascular risk associated with uncontrolled HTN, particularly elevated SBP levels.
PMCID: PMC1490067  PMID: 15836524
hypertension; systolic blood pressure; patient awareness
5.  Quality of care for hypertension in the United States 
Despite heavy recent emphasis on blood pressure (BP) control, many patients fail to meet widely accepted goals. While access and adherence to therapy certainly play a role, another potential explanation is poor quality of essential care processes (QC). Yet little is known about the relationship between QC and BP control.
We assessed QC in 12 U.S. communities by reviewing the medical records of a randomly selected group of patients for the two years preceding our study. We included patients with either a diagnosis of hypertension or two visits with BPs of ≥140/90 in their medical records. We used 28 process indicators based on explicit evidence to assess QC. The indicators covered a broad spectrum of care and were developed through a modified Delphi method. We considered patients who received all indicated care to have optimal QC. We defined control of hypertension as BP < 140/90 in the most recent reading.
Of 1,953 hypertensive patients, only 57% received optimal care and 42% had controlled hypertension. Patients who had received optimal care were more likely to have their BP under control at the end of the study (45% vs. 35%, p = .0006). Patients were more likely to receive optimal care if they were over age 50 (76% vs. 63%, p < .0001), had diabetes (77% vs. 71%, p = .0038), coronary artery disease (87% vs. 69%, p < .0001), or hyperlipidemia (80% vs. 68%, p < .0001), and did not smoke (73% vs. 66%, p = .0005).
Higher QC for hypertensive patients is associated with better BP control. Younger patients without cardiac risk factors are at greatest risk for poor care. Quality measurement systems like the one presented in this study can guide future quality improvement efforts.
PMCID: PMC546215  PMID: 15638933
6.  UMLS Concept Indexing for Production Databases 
Objectives: To explore the feasibility of using the National Library of Medicine's Unified Medical Language System (UMLS) Metathesaurus as the basis for a computational strategy to identify concepts in medical narrative text preparatory to indexing. To quantitatively evaluate this strategy in terms of true positives, false positives (spuriously identified concepts) and false negatives (concepts missed by the identification process).
Methods: Using the 1999 UMLS Metathesaurus, the authors processed a training set of 100 documents (50 discharge summaries, 50 surgical notes) with a concept-identification program, whose output was manually analyzed. They flagged concepts that were erroneously identified and added new concepts that were not identified by the program, recording the reason for failure in such cases. After several refinements to both their algorithm and the UMLS subset on which it operated, they deployed the program on a test set of 24 documents (12 of each kind).
Results: Of 8,745 matches in the training set, 7,227 (82.6 percent ) were true positives, whereas of 1,701 matches in the test set, 1,298 (76.3 percent) were true positives. Matches other than true positive indicated potential problems in production-mode concept indexing. Examples of causes of problems were redundant concepts in the UMLS, homonyms, acronyms, abbreviations and elisions, concepts that were missing from the UMLS, proper names, and spelling errors.
Conclusions: The error rate was too high for concept indexing to be the only production-mode means of preprocessing medical narrative. Considerable curation needs to be performed to define a UMLS subset that is suitable for concept matching.
PMCID: PMC134593  PMID: 11141514
7.  GEM 
Objective: To develop a guideline document model that includes a sufficiently broad set of concepts to be useful throughout the guideline life cycle.
Design: Current guideline document models are limited in that they reflect the specific orientation of the stakeholder who created them; thus, developers and disseminators often provide few constructs for conceptualizing recommendations, while implementers de-emphasize concepts related to establishing guideline validity. The authors developed the Guideline Elements Model (GEM) using XML to better represent the heterogeneous knowledge contained in practice guidelines. Core constructs were derived from the Institute of Medicine's Guideline Appraisal Instrument, the National Guideline Clearinghouse, and the augmented decision table guideline representation. These were supplemented by additional concepts from a literature review.
Results: The GEM hierarchy includes more than 100 elements. Major concepts relate to a guideline's identity, developer, purpose, intended audience, method of development, target population, knowledge components, testing, and review plan. Knowledge components in guideline documents include recommendations (which in turn comprise conditionals and imperatives), definitions, and algorithms.
Conclusion: GEM is more comprehensive than existing models and is expressively adequate to represent the heterogeneous information contained in guidelines. Use of XML contributes to a flexible, comprehensible, shareable, and reusable knowledge representation that is both readable by human beings and processible by computers.
PMCID: PMC79044  PMID: 10984468
8.  Exploring Performance Issues for a Clinical Database Organized Using an Entity-Attribute-Value Representation 
Background: The entity-attribute-value representation with classes and relationships (EAV/CR) provides a flexible and simple database schema to store heterogeneous biomedical data. In certain circumstances, however, the EAV/CR model is known to retrieve data less efficiently than conventionally based database schemas.
Objective: To perform a pilot study that systematically quantifies performance differences for database queries directed at real-world microbiology data modeled with EAV/CR and conventional representations, and to explore the relative merits of different EAV/CR query implementation strategies.
Methods: Clinical microbiology data obtained over a ten-year period were stored using both database models. Query execution times were compared for four clinically oriented attribute-centered and entity-centered queries operating under varying conditions of database size and system memory. The performance characteristics of three different EAV/CR query strategies were also examined.
Results: Performance was similar for entity-centered queries in the two database models. Performance in the EAV/CR model was approximately three to five times less efficient than its conventional counterpart for attribute-centered queries. The differences in query efficiency became slightly greater as database size increased, although they were reduced with the addition of system memory. The authors found that EAV/CR queries formulated using multiple, simple SQL statements executed in batch were more efficient than single, large SQL statements.
Conclusion: This paper describes a pilot project to explore issues in and compare query performance for EAV/CR and conventional database representations. Although attribute-centered queries were less efficient in the EAV/CR model, these inefficiencies may be addressable, at least in part, by the use of more powerful hardware or more memory, or both.
PMCID: PMC79043  PMID: 10984467
9.  Organization of Heterogeneous Scientific Data Using the EAV/CR Representation 
Entity-attribute-value (EAV) representation is a means of organizing highly heterogeneous data using a relatively simple physical database schema. EAV representation is widely used in the medical domain, most notably in the storage of data related to clinical patient records. Its potential strengths suggest its use in other biomedical areas, in particular research databases whose schemas are complex as well as constantly changing to reflect evolving knowledge in rapidly advancing scientific domains. When deployed for such purposes, the basic EAV representation needs to be augmented significantly to handle the modeling of complex objects (classes) as well as to manage interobject relationships. The authors refer to their modification of the basic EAV paradigm as EAV/CR (EAV with classes and relationships). They describe EAV/CR representation with examples from two biomedical databases that use it.
PMCID: PMC61391  PMID: 10579606

Results 1-10 (10)