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Biomedical subjects

C F Arkin

Publications and source records attributed to C F Arkin.

7 recordsLinked to original sources

Hyperfibrinogenemia. An important risk factor for vascular complications in diabetes.

OBJECTIVE: To evaluate the determinants of elevated fibrinogen levels and the impact of hyperfibrinogenemia on vascular complications in diabetes. RESEARCH DESIGN AND METHODS: Plasma fibrinogen, glucose, HbA1, and lipids were measured in 116 ambulatory type I and type II diabetic patients with (n = 59) or without (n = 57) clinical evidence of micro- or macrovascular complications. In 56 of these patients, factor VII activity and CRP also were measured. Univariate and multivariate data analyses were conducted. RESULTS: Overall mean +/- SE fibrinogen levels in patients (339 +/- 7.3 mg/dl) were elevated markedly compared with control subjects (248 +/- 9.1 mg/dl). Fibrinogen levels were elevated disproportionately in patients with type II diabetes (P less than 0.0001), hypertension (P = 0.0001), obesity (P less than 0.0001), and vascular complications (P less than 0.0001). Fibrinogen was correlated significantly with age (P less than 0.001), cholesterol (P = 0.002), CRP (P less than 0.001), and factor VII activity (P = 0.032), but not with plasma glucose, triglycerides, HDL cholesterol, or disease duration. Stepwise multiple regression analyses revealed that type II diabetes and presence of vascular complications were major determinants of fibrinogen. For vascular complications, fibrinogen emerged as one of only three independent predictors, the other two being diabetes duration and hypertension.

Analysis of Variance

Factors affecting the performance of factor VIII coagulant activity assays. Results of proficiency surveys of the College of American Pathologists.

To evaluate sources of interlaboratory variation in factor VIII coagulant assays and the effects of uniform calibration on it, data were analyzed from Survey Set H2-C, 1987, of the College of American Pathologists, Northfield, Ill, into which the College of American Pathologists Reference Preparation for Factor VIII was incorporated. Peer group performance and its improvement by uniform calibration were evaluated by comparing means, precisions, and numbers of acceptable survey scores. Results showed a poorer performance by less experience laboratories and by those that used undesirable calibrators. Substantial improvement was seen with uniform calibration, especially among laboratories that had employed poorer calibrators. Although variance component analysis showed that the type of calibrator was the most important contributor to interlaboratory variation, it accounted for only 10% of total variability. Participant summaries and questionnaires that spanned several years revealed steady improvement in methodology but no striking changes in interlaboratory variation.

Analysis of Variance

Tissue calcification after orthotopic liver transplantation. An autopsy study.

A retrospective review of 25 patients who underwent orthotopic liver transplantation was performed to relate the prevalence and preferred sites of microscopic calcium deposition seen at autopsy to clinical parameters, namely, hypercalcemia, hypercalcemia, hyperphosphatemia, and renal failure. Microscopic foci of calcification were noted in 84% of patients, and hypercalcemia was noted in 68%. Multiple regression analysis demonstrated that the number of microscopically calcified organs depended in part on the peak total serum calcium level and the duration of hypercalcemia and that the peak total serum calcium level depended in part on the peak phosphorus level and the quantity of calcium administered intraoperatively. Univariate analysis showed that peak phosphorus level was partially dependent on the peak creatinine level. The data suggest that hypercalcemia and postoperative ectopic calcification are common and related occurrences following hepatic transplantation and that intraoperative manipulations of serum calcium levels and renal failure partially, but not entirely, account for this phenomenon.

Adult

The hypercoagulability states.

Although interest in coagulation has usually centered about the various hemorraghic disorders, it is hyperactivity of the hemostatic system with its thrombotic complications which has a far greater clinical impact. The hypercoagulability states are a vague group of disorders not well defined by the laboratory. They fall into two distinct groups: (1) conditions promoting venous thrombosis by activating the coagulation mechanism and (2) conditions promoting arterial thrombosis by platelet plug formation. Dealing with both of these groups separately the various disorders associated with a hypercoagulable state are discussed as well as their pathophysiologic basis; Special emphasis is placed on the laboratory evaluation of these disorders.

Blood Coagulation

An automatic leukocyte analyzer. Validity of its results.

A statistical study was undertaken to evaluate the Corning Larc Leukocyte Analyzer by comparing its results with those of 20 medical technologists with regard to reproducibility and degree of agreement. A special effort was made to use statistically quantitative comparisons, large numbers of samples, and a large group of technologists. The results of the Larc are frequently more reproducible than those of technologists, especially for bands and segmented neutrophils. Other comparative studies show that the Larc reports clinically equivalent proportions of the different cell types normal and abnormal. This is true for case by cases as well as cumulative comparisons. All known cases of leukemia was detected by the Larc during the study, although the number of samples from leukemia patients was small (11 of 700).

Animals

Vancomycin stability in heparin and total parenteral nutrition solutions: novel approach to therapy of central venous catheter-related infections.

To facilitate therapy of central venous catheter-related Gram-positive bacterial infection in patients who require total parenteral nutrition (TPN) therapy, we studied the stability of vancomycin in a commonly used TPN solution (V-TPN) at final concentrations of 0.5 mg/mL and 1.0 mg/mL and in heparin (100 U/mL in 0.9% NaCl) at 25 micrograms/mL (V-H). Vancomycin concentrations in V-TPN and V-H after storage at 4 degrees C over 35 and 14 days, respectively, were stable (within 10% of the prestorage vancomycin concentration). After 14 days at 4 degrees C heparin activity in V-H solution was 100 +/- 4% of that noted initially. Vancomycin remained stable (100 +/- 6% of the original vancomycin concentration) when the previously refrigerated V-TPN was held for an additional 24 hours at 22 degrees C. When the previously refrigerated V-H was held for an additional 24 hours at 37 degrees C, vancomycin concentrations decreased to 78 +/- 9% of the baseline concentrations (p less than .001). The stability of vancomycin in this TPN solution allows the daily dose of vancomycin to be mixed with the solution and then infused over 10 hours. As shown with pharmacokinetic modeling, this form of therapy will achieve serum vancomycin concentrations within the therapeutic range throughout a 24-hour period. The relative stability of vancomycin in a heparin line-flush solution allows vancomycin concentration in the lumen of the catheter to be maintained at greater than or equal to 15 micrograms/mL during the interval between catheter flushing and the subsequent TPN infusion. A simplified method of administering vancomycin to patients receiving concurrent TPN is possible.

Catheterization, Central Venous