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Biomedical subjects

G J Vanscoy

Publications and source records attributed to G J Vanscoy.

5 recordsLinked to original sources
PubMed1991

Warfarin and the international normalized ratio: reducing interlaboratory effects.

In North America, the dose of warfarin has been unintentionally increased during the past two decades because of failure to recognize the effect on the anticoagulation test of less sensitive tissue thromboplastins. Although there still is some controversy, the suggested dose of warfarin has now been adjusted downward to reduce the risk of bleeding. These revised dosing recommendations incorporate the international normalized ratio (INR), which takes into account the source of thromboplastin. However, there is considerable variability in the sensitivities of thromboplastin from manufacturer to manufacturer and lot to lot. Therefore, prothrombin times (PTs) are not comparable from laboratory to laboratory without knowing the sensitivity of the thromboplastin. Unless laboratories adopt a standardized tissue thromboplastin, the PT should be reported as an INR.

Humans↗
PubMed1991

Exaggerated warfarin sensitivity: a case report.

A 64-y-old male was hospitalized because of significant bleeding and a prolonged prothrombin time (PT) (greater than 200 sec) following an inadvertent doubling of his anticoagulant dose. He was previously well controlled on 2.5 mg warfarin every fourth day. Treatment included vitamin K, fresh frozen plasma, and packed red blood cells. Warfarin plasma concentrations, clotting factor analysis (CFA) and PTs were analyzed to evaluate this patient. Following hospitalization, the patient was followed by the Anticoagulation Clinic and his dose was stabilized at 0.5 mg daily. He experienced no further bleeding episodes and his PT ratio was maintained at 1.5 times control. The response to a dose of warfarin varies greatly from patient to patient. Previous reports of abnormal responses to warfarin can be categorized as either warfarin "resistant" or "sensitive." The preponderance of reports are compliance or hereditary warfarin resistance. This patient represents a case of exaggerated warfarin sensitivity that cannot be easily explained. There was no evidence of a drug interaction, warfarin concentrations were not excessive, and CFA was reflective of a moderate warfarin effect. Extreme tissue sensitivity to warfarin is a plausible explanation for this abnormal response.

Blood Coagulation Factors↗
PubMedDate not supplied

Survey and evaluation of newsletters marketed to family physicians.

BACKGROUND: Newsletters are marketed to physicians to provide a concise, accurate, and timely overview of the medical literature. The goal of these newsletters seems to be to present information that can be a suitable substitute for reading the original article. The purpose of this paper is to describe and evaluate newsletters pertinent to family physicians. METHODS: Newsletters appropriate for family physicians were selected by collecting newsletter advertisements and by searching newsletter directories. A 3-month sample and pertinent data were collected from the publishers. Evaluation criteria included accuracy and completeness of the abstracts, scope of coverage of the medical literature, and relevance of article sources. RESULTS: Eight newsletters were collected and evaluated. Accuracy was high for the evaluated abstracts. Abstract completeness averaged only 70 percent (range 55 percent to 92 percent). The type and source of abstracted articles varied widely among the newsletters. CONCLUSION: Newsletters available to family physicians vary widely; personal evaluation should supplement the results of the evaluation.

Costs and Cost Analysis↗