Prognostic significance of in vitro marrow culture growth pattern in untreated acute nonlymphocytic leukemia

The growth pattern of marrow cells in agar culture was studied in 90 adult patients with acute nonlymphocytic leukemia (ANLL) at diagnosis. We classified the abnormal growth patterns into 4 groups, A: no growth, B: decreased growth, C: excessive microcluster formation and D: excessive cluster growth with more than 20 colonies. There was a good correlation between growth pattern and FAB subtype. A predominance of group A growth was observed in M1, while group B growth was found in 50% of patients with M2 and M5. No relationships between the growth patterns and other clinical parameters were detected. Sixty-six patients were evaluable for treatment outcome. The growth pattern significantly correlated with complete remission rate. The remission rates were 52, 87, 80, and 25% for patients with group A, B, C and D growth, respectively. Analyses of remission duration and survival curves showed significant differences among the different growth patterns. Patients with D growth experienced a shorter remission duration and a lower survival rate than other groups. These results indicate that the in vitro culture growth pattern in untreated ANLL is of prognostic significance in predicting the response to therapy.     

Clinical and angiographic variables affecting the progression of coronary artery disease as determined by quantitative angiography

To assess by serial quantitative angiography, the significance of clinical and angiographic variables that affect the progression of coronary artery disease (CAD). Progression of disease by sequential angiography is unpredictable and the role of clinical risk factors controversial. Various intervention trials have demonstrated less progression and even regression in hyperlipidemic patients. Correlates of progression have included a younger age, unstable angina, and greater involvement of the coronary arteries, with few studies looking at angiographic features of individual lesions. Serial angiograms on 74 patients were analyzed by computer assisted quantitative angiography using absolute measurements. A total of 99 diseased segments were analyzed for progression defined as an absolute reduction of 20% in luminal cross-sectional area. A preliminary correlation coefficient was calculated for each of the clinical and angiographic variables to detect any association with progression, and the odds ratio determined.The presence of any of the clinical risk factors-diabetes, hypertension, serum cholesterol, smoking, and a family history of coronary disease could not predict progression. The use of beta blockers was three times less likely to be associated with progression (odds ratio 0.33). While the presence of distal disease was associated with progression of a more proximal lesion (odds ratio 2.4), eccentricity, branch point location, lesion length, calcification, thrombus, or the presence of collaterals did not influence progression of disease in an individual segment. In conclusion, the presence of any of the clinical risk factors could not predict progression of disease in an individual coronary segment as determined by serial quantitative angiography, and the use of beta blockers and the absence of coexistent distal disease was associated with less progression of disease in an individual coronary segment. This may be related to changes in wall stress, reduced platelet interactions, and the integrity and permeability of the vascular endothelium to lipids.     

Temperature prediction in high speed bone grinding using motor PWM signal

This research explores the feasibility of using motor electrical feedback to estimate temperature rise during a surgical bone grinding procedure. High-speed bone grinding is often used during skull base neurosurgery to remove cranial bone and approach skull base tumors through the nasal corridor. Grinding-induced heat could propagate and potentially injure surrounding nerves and arteries, and therefore, predicting the temperature in the grinding region would benefit neurosurgeons during the operation. High-speed electric motors are controlled by pulse-width-modulation (PWM) to alter the current input and thus maintain the rotational speed. Assuming full mechanical to thermal power conversion in the grinding process, PWM can be used as feedback for heat generation and temperature prediction. In this study, the conversion model was established from experiments under a variety of grinding conditions and an inverse heat transfer method to determine heat flux. Given a constant rotational speed, the heat conversion was represented by a linear function, and could predict temperature from the experimental data with less than 20% errors. Such results support the advance of this technology for practical application.     

A pulsatile blood vessel system for a femoral arterial access clinical simulation model

The model-based, rapid-prototyping-enabled design and manufacture of a pulsatile blood vessel (PBV) for high-fidelity mannequin-based clinical simulations is presented. The PBV presented here is a pressurized, flexible tube with alternating fluid pressure created by a pump to mimic the behavior of a human vessel in response to pulsatile pressure. The use of PBVs is important for the fidelity of a clinical simulator that requires residents to palpate and/or access the vessel. In this study, a PBV is presented which features the integration of 3D modeling using patient-specific computed tomography (CT) data, mold fabrication using rapid-prototyping, and finite element method for estimating the required pumping pressure to generate the same level of force (about 1.5 N) experienced by the user through palpation. The relationship between this palpation force and the vessel pressure is studied using two strategies: finite element analysis (FEA) and experiments in a femoral arterial access simulator with a pump, artificial vessel, and surrounding phantom tissue. The experimental results show a discrepancy of 8.7% from the FEA-predicted value. Qualitative validation is done by exposing and surveying 19 interventional cardiology residents at four major educational institutions to the simulator for accuracy of its feel. The overall survey results are positive.