OBJECTIVE: To compare a new configuration of proximal wires for hybrid external fixation with the standard configuration. DESIGN: Biomechanical testing of five matched pairs of fresh cadaveric tibia. INTERVENTION: The authors compared the standard tension wire configuration of the three proximal wires with a more sagittal orientation of the oblique wires. A second study compared the new configuration with two wires and an offset half-pin. A two-centimeter segmental defect was created just distal to the tibial tubercle and the tibias fixed in a Montecelli Spinelli (Howmedica, NJ, U.S.A.) hybrid frame. The constructs were biomechanically tested using an Instron servohydraulic biaxial testing machine. RESULTS: There was a significant 67 percent decrease in displacement during anterior posterior bending and a significant 40 percent decrease in displacement in posterior bending with the new configuration compared with the standard configuration (p < 0.05). The differences in stability in all other testing modes were not significant. There was no significant difference between the new configuration and the two wire and off-set half-pin configuration. CONCLUSION: We recommend anterior placement of the oblique tension wires in the proximal tibia to more effectively resist bending in the sagittal plane, which is the most common deforming force on proximal metaphyseal fractures.

Biomechanical Phenomena↗

PubMedDate not supplied

Benefits of an object-oriented database representation for controlled medical terminologies.

OBJECTIVE: Controlled medical terminologies (CMTs) have been recognized as important tools in a variety of medical informatics applications, ranging from patient-record systems to decision-support systems. Controlled medical terminologies are typically organized in semantic network structures consisting of tens to hundreds of thousands of concepts. This overwhelming size and complexity can be a serious barrier to their maintenance and widespread utilization. The authors propose the use of object-oriented databases to address the problems posed by the extensive scope and high complexity of most CMTs for maintenance personnel and general users alike. DESIGN: The authors present a methodology that allows an existing CMT, modeled as a semantic network, to be represented as an equivalent object-oriented database. Such a representation is called an object-oriented health care terminology repository (OOHTR). RESULTS: The major benefit of an OOHTR is its schema, which provides an important layer of structural abstraction. Using the high-level view of a CMT afforded by the schema, one can gain insight into the CMT's overarching organization and begin to better comprehend it. The authors' methodology is applied to the Medical Entities Dictionary (MED), a large CMT developed at Columbia-Presbyterian Medical Center. Examples of how the OOHTR schema facilitated updating, correcting, and improving the design of the MED are presented. CONCLUSION: The OOHTR schema can serve as an important abstraction mechanism for enhancing comprehension of a large CMT, and thus promotes its usability.

Classification↗

PubMedDate not supplied

Representing the UMLS as an object-oriented database: modeling issues and advantages.

OBJECTIVE: The Unified Medical Language System (UMLS) combines many well-established authoritative medical informatics terminologies in one knowledge representation system. Such a resource is very valuable to the health care community and industry. However, the UMLS is very large and complex and poses serious comprehension problems for users and maintenance personnel. The authors present a representation to support the user's comprehension and navigation of the UMLS. DESIGN: An object-oriented database (OODB) representation is used to represent the two major components of the UMLS-the Metathesaurus and the Semantic Network-as a unified system. The semantic types of the Semantic Network are modeled as semantic type classes. Intersection classes are defined to model concepts of multiple semantic types, which are removed from the semantic type classes. RESULTS: The authors provide examples of how the intersection classes help expose omissions of concepts, highlight errors of semantic type classification, and uncover ambiguities of concepts in the UMLS. The resulting UMLS OODB schema is deeper and more refined than the Semantic Network, since intersection classes are introduced. The Metathesaurus is classified into more mutually exclusive, uniform sets of concepts. The schema improves the user's comprehension and navigation of the Metathesaurus. CONCLUSIONS: The UMLS OODB schema supports the user's comprehension and navigation of the Metathesaurus. It also helps expose and resolve modeling problems in the UMLS.

Databases as Topic↗

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Study of educational deficits as the cause of hospital admission for diabetes mellitus in a community hospital.

Seventy-eight consecutive patients admitted to a community hospital for diabetic complications over a 1-yr period were interviewed in regard to circumstances resulting in their hospitalization. Based on this interview, patients were categorized as to the cause for admission into three groups: (1) educational deficits; (2) psycho-socio-economic deficits; and (3) unavoidable hospital admission. Twenty-seven percent of the patients had a specific educational deficit which was judged to be responsible for their hospitalization; an additional 20% of patients had combined education and psycho-socio-economic deficits accounting for their admission.

Diabetes Complications↗

PubMedDate not supplied

Overview of enzyme inhibitors and anti-androgens in prostatic cancer.

Surgical castration and estrogen therapy for prostate cancer were developed in 1941, and have been shown to improve both quality of life and survival. Little change in the therapeutics of prostate cancer has occurred over the subsequent three decades. In the 1970s, the progestational anti-androgens, ketoconazole and flutamide, were introduced as androgen-blocking agents, and have been shown to block at least partially both adrenal and testicular androgens. Gonadotropin-releasing hormone (GnRH) agonists were shown in the 1980s to produce medical castration without the cardiac and cerebrovascular risks of standard dose estrogen. In the 1980s, large-scale, multicenter, double-blind studies were done to compare the effect of combined androgen blockade, using multiple drugs, to single-drug blockade of gonadal androgen with regard to time to progression and survival in stage D2 cancer. These studies were done to test theories regarding the role of adrenal androgens and their effects on androgen-sensitive tumor clones in prostate cancer. The theory of clonal heterogeneity, particularly with regard to androgen sensitivity, has led to the continuation of three major controversies about the management of prostate cancer: Is combined blockade of testicular and adrenal androgens in stage D2 prostate cancer more effective than gonadal androgen blockade alone? What is the optimal secondary or tertiary therapy for relapsed prostate cancer? Is there any advantage for combined androgen blockade at the start of therapy in stage D2 prostate cancer as compared to sequential therapy with blockade of testicular androgens first, and then adrenal androgens at the time of relapse?

Androgen Antagonists↗

PubMedDate not supplied

Psychiatric nurses and the law: adversaries or partners?

Explore the source record for details and available documents.

Humans↗

PubMedDate not supplied

Recombinant methioninase infusion reduces the biochemical endpoint of serum methionine with minimal toxicity in high-stage cancer patients.

The tumor-specific increased minimal requirement for methionine has been shown to be a highly promising therapeutic target. To attack this target we have previously cloned the methioninase gene from Pseudomonas putida and produced recombinant methioninase (rMETase). A pilot Phase I clinical trial has been carried out to determine rMETase toxicity, rMETase pharmacokinetics, and serum MET-depletion in cancer patients. Patients with advanced breast cancer, lung cancer, renal cancer and lymphoma were given a single rMETase treatment at doses ranging from 5,000 to 20,000 units by i.v. infusion over 6-24 hours. No clinical toxicity was observed in any patient after rMETase treatment. rMETase levels reached 0.1 to 0.4 units per ml of serum in the patients which correspond to therapeutic levels in vitro. The lowest serum methionine levels in rMETase-treated patients were 0.1% of the pre-treatment levels corresponding to approximately 0.1 microM, which also correlates to therapeutic levels in vitro. The results of the rMETase pilot Phase I clinical trial therefore indicate that i.v. infusion of rMETase is safe and effectively depletes its biochemical target of serum methionine suggesting potential efficacy in future clinical trials.

Antimetabolites, Antineoplastic↗