A claims-based Markov model for Crohn's disease.

BACKGROUND: Crohn's disease is a chronic condition that often presents in early adulthood. AIM: To evaluate health care costs and costs per quality-adjusted life year (QALY) for Crohn's disease. METHODS: A Markov model was developed using administrative claims data for patients aged > or = 18 years with > or = 3 years of continuous enrolment from 2000 to 2008 and > or =2 Crohn's disease claims. Disease states (remission, mild-moderate, moderate-severe, and severe-fulminant) were defined using the American College of Gastroenterology treatment guidelines criteria. Transition probabilities were calculated from consecutive 6-month periods. Costs were determined from paid claims and QALY utilities were obtained from the literature. The model assumed a 30-year-old patient at the time of entry into the model. RESULTS: There were 40 063 patients identified, with a total of 420 773 cycles [remission (197 111; 46.8%), mild-moderate (44 024; 10.5%), moderate-severe (132 695; 31.5%), severe-fulminant (46 925; 11.2%)]. The costs/QALY for remission, mild-moderate, moderate-severe, and severe-fulminant disease states respectively were $2896, $8428, $11 518 and $69 277 for males and $2896, $8426, $22 633 and $69 412 for females. CONCLUSIONS: Overall, health care costs for patients with Crohn's disease increased with disease severity. Although the probabilities of transitioning from other health states to the severe-fulminant disease state were low, the cost/QALY was high.

Inhibition of monocyte esterase activity by organophosphate insecticides.

Organophosphate insecticides, such as Vapona, Naled, and Rabon, are highly potent inhibitors of an enzyme found in human monocytes. The enzyme, a specific monocyte esterase, could be inhibited by Vapona in blood samples via airborne contamination at levels easily achieved from commercial slow-release insecticide strips. Fifty percent inhibition (I50)--as measured on the Hemalog D (Technicon Corp.)--occurred at solution concentrations of 0.22, 1.5, and 2.6 X 10(-6) g/liter for Vapona, Rabon, and Naled, respectively. Parathion (a thiophosphate) and Baygon (a carbamate) were less potent, with I50 values of 3.7 X 10(-5) and 1.5 X 10(-4) g/liter, respectively. Dursban (another thiophosphate) and Carbaryl (a carbamate) showed only marginal inhibition. Eserine, malathion, nicotine and pyrethrum had no inhibitory effect up to 0.5 g/liter. The occurrence of this effect in vivo has not yet been shown, nor is it clear what the implications of such an effect would be. The inhibition of this enzyme by airborne contaminants, however, may interfere with the proper functioning of the Hemalog D.

Automation of the indirect fluorescent-antibody test for toxoplasmosis.

The feasibility of automating the decision-making tasks of the medical technician in the determination of the results of the indirect fluorescent-antibody test for toxoplasmosis was investigated. Two approaches were studied: (i) macroscopic measurement of fluorescence from a large number of organisms (full-field illumination measurements), and (ii) microscopic measurements of fluorescence and morphology of individual parasites (pattern recognition). The macroscopic approach was studied utilizing an argon-ion laser in incident illumination with a Leitz Ortholux microscope and a phototube mounted so as to measure green fluorescence. Due to similar amounts of fluorescence from negative polar reactions and positive rim reactions, the macroscopic technique was concluded to be not feasible. The microscopic approach was studied utilizing a high resolution optical pattern recognition instrument. The results indicate that an object area measurement is sufficient to distinguish the presence of Toxoplasma gondii organisms from debris and overlapping organisms when studying the red fluorescence (due to Evans blue counterstain). Dark reactions were determined by the absence of green fluorescence. The differentiation of the rim and polar reactions was determined by the measurement of the ratio of green fluorescing area (due to fluorescein isothiocyanate) to red fluorescing area on the same organism. Clinically important titer information was also demonstrated to be obtainable. It was concluded that complete automation of the indirect fluorescent antibody test for toxoplasmosis is feasible with existing technology.