Electromagnetic compatibility aspects of active robotic systems for surgery: the robotic prostatectomy experience

This case describes ventricular proarrhythmia as a result of a synchronized internal atrial defibrillation shock in a 29-year-old man with Ebstein's anomaly referred for radiofrequency ablation of a right posterior accessory pathway. During the electrophysiologic study, atrial fibrillation was induced and 3/3 msec shocks of various strengths were delivered between two decapolar defibrillation catheters in the coronary sinus and right atrial appendage. A 2.0-J biphasic shock synchronized to an R wave after a short-long-short ventricular cycle length pattern with a preshock coupling interval of 245 msec induced ventricular fibrillation, which was externally defibrillated with 200 J. This observation has implications for the development of implantable atrial defibrillators.     

Cytokine priming reduces dependence on TNF-R2 for TNF-alpha-mediated induction of macrophage nitric oxide generation

In the presence of interferon-gamma (IFN-gamma), human tumor necrosis factor-alpha (Hu-TNF-alpha), which binds to murine TNF-alpha receptor type 1 (TNF-R1) but not to murine TNF-R2, was effective in inducing nitric oxide (NO) production in spleen-derived macrophages (M phi), albeit at concentrations 12.5-fold greater than those required by murine TNF-alpha (Mu-TNF-alpha), to achieve the same result. Addition of anti-TNF-R1 completely inhibited the Mu-TNF-alpha-mediated induction of NO, demonstrating that TNF-R1 is critical to the IFN-gamma-dependent TNF-alpha-mediated induction of M phi effector function. However, treatment with anti-TNF-R2 resulted in a partial inhibition of M phi activation. Spleen-derived M phi were more dependent on TNF-R2 than RAW 264.7 or peritoneal M phi based on their responsiveness to Hu-TNF-alpha. Priming of spleen-derived M phi with either IFN-gamma or granulocyte-macrophage colony-stimulating factor (GM-CSF) heightened the maximal responses to both TNF-alpha species and increased the overall effectiveness of Hu-TNF-alpha without increasing expression of either TNF-alpha receptor. The dependence of spleen-derived M phi on both TNF-alpha receptors for signaling the induction of effector function supports an active signaling role for TNF-R2 in its synergy with TNF-R1 rather than a passive ligand passing role.     

Clinical effects of longitudinal division of the corpus callosum in normal dogs

Longitudinal division of the corpus callosum was performed in six normal beagles to determine surgical morbidity. The corpus callosum was divided sagittally on the midline and the effect on neurological function was determined. Five of six dogs were clinically normal within 14 days or less after surgery. One dog had persistent but improving clinical signs consistent with a forebrain disturbance at 30 days after surgery. Overall, minimal morbidity and no mortality was associated with this surgical procedure. Further study is indicated to determine the efficacy of this surgical treatment for seizure control in dogs with idiopathic epilepsy.     

Heat tolerance in Tuli-, Senepol-, and Brahman-sired F1 Angus heifers in Florida

We investigated heat tolerance and growth rate in two trials under ambient conditions in central Florida. Trial 1 (1994) involved 38 Brahman (B), 21 Senepol (S), 19 B x Angus (A), 20 S x A, and 20 Tuli (T) x A heifers. Trial 2 (1995) involved 13 A, 35 B, 30 S, 23 B x A, 17 S x A, and 28 T x A heifers. Measurements were made on three consecutive weeks during the hotter and cooler seasons of each year and included rectal temperature (RT, degrees C), respiration rate (RR, bpm), temperament score (TS; 1 = very docile, 5 = very aggressive), blood packed-cell volume (PCV), and plasma cortisol concentration (CORT). Data for RT were transformed (log10 [RT - 37]) before analysis. On the hottest date in Trial 1, log10 RT was not different between B (.39 +/- .011) and B x A (.37 +/- .016) or between T x A (.35 +/- .015) and B x A, but log10 RT was lower (P < .05) in S x A (.30 +/- .015) than in either S (.35 +/- .015) or T x A. On all dates in Trial 1, RR was lower (P < .05 to .001) and PCV was higher (P < .05 to .001) in B than in B x A. There were few differences in TS except on two dates when B scored higher (P < .01 to .001) than B x A, and these differences were associated with higher (P < .05) CORT in B than in B x A. Using initial BW as a covariate, adjusted ADG (kg) of T x A (.52 +/- .023) was not different from adjusted ADG of B x A (.57 +/- .024) or S x A (.54 +/- .023). On the hottest date in Trial 2, log10 RT and RR were higher (P < .001) in A (.59 +/- .017, 74 +/- 2.7) than in B (.47 +/- .010, 39 +/- 1.6), S (.42 +/- .011, 50 +/- 1.8), and crossbred heifers (.47 +/- .011, 60 +/- 1.8; .43 +/- .014, 55 +/- 2.4; and .50 +/- .012, 48 +/- 2.0 for T x A, S x A and B x A, respectively), and RR was higher (P < .001) in B x A than in B. On the coolest date in Trial 2, RR was slightly lower in B (32 +/- .5) than in A(34 +/- .7, P < .01) and B x A (36 +/- .6, P < .001) and was associated with higher PCV in B than in A. On both dates, TS and CORT were higher (P < .01) in B than in A. In Trial 2, adjusted ADG (kg) was higher (P < .01) in B (.43 +/- .017) than in A (.32 +/- .033), higher (P < .001) in S (.45 +/- .018) than in A, and higher (P < .001) in crossbreds (B x A [.53 +/- .023] + S x A [.44 +/- .025] + T x A [.46 +/- .019]) than in A. These data indicate that heat tolerance in F1 crosses of tropically adapted breeds (Tuli, Senepol, Brahman) with a temperate breed (Angus) is similar to heat tolerance displayed by purebred tropical breeds (Senepol, Brahman).     

Design, synthesis, and conformational analysis of a novel series of HIV protease inhibitors

A combination of structure-based design and both solution, and solid-phase synthesis were utilized to derive a potent (nM) series of HIV-1 protease inhibitors bearing a structurally novel backbone. Detailed structural analysis of several inhibitors prepared in this series has suggested that rigidification of the P1/P2 region of this class of molecules may result in compounds with improved potency.     

A flexible PC-based physiological monitor for animal experiments

We have developed a flexible physiological monitoring and analysis system for physiological studies in which data are obtained over extended periods. Our system uses low-cost personal computer hardware to concentrate data from existing multiple monitoring devices. All monitored parameters are displayed on a single screen and recorded in a single file. The system automates the process of physiological record keeping by providing continuous displays of vital signs. In addition, audible and visual alarms are produced when vital signs are outside of acceptable ranges, prompting the experimenter to take corrective actions. The central element of the system is a program running in a dedicated manner on an IBM PC-compatible computer. The program is written in the C language and makes use of a graphics library to display traces and analysis results in real time on any standard display for the PC. This program assigns the analog channels of an A/D board to particular physiological parameters by initially reading a configuration file, which also describes the alarm conditions and analysis routine for each parameter. All hardware specific code is isolated into well-defined modules. The program is both highly flexible with regard to different sets of parameters and highly portable for different experimental and computer environments.     

Effects of age, breast density, ethnicity, and estrogen replacement therapy on screening mammographic sensitivity and cancer stage at diagnosis: review of 183,134 screening mammograms in Albuquerque, New Mexico

PURPOSE: To examine how common patient factors affect screening mammographic sensitivity and cancer stage at diagnosis. MATERIALS AND METHODS: The authors used a population-based database of 183,134 screening mammograms and a statewide tumor registry to identify 807 breast cancers detected at screening mammography. RESULTS: Sensitivity varied significantly with ethnicity, use of estrogen replacement therapy, mammographic breast density, and age. Sensitivity was 54% (13 of 24) in women younger than 40 years, 77% (121 of 157) in women aged 40-49 years, 78% (224 of 286) in women aged 50-64 years, and 81% (277 of 340) in women older than 64 years. Sensitivity was 68% (162 of 237) for dense breasts and 85% (302 of 356) for nondense breasts and 74% (180 of 244) in estrogen replacement therapy users and 81% (417 of 513) in nonusers. Sensitivity was most markedly reduced with the combination of dense breasts and estrogen replacement therapy use; there was little difference when only one factor was present. Median cancer size and the percentage of early cancers showed little change with any factors. CONCLUSION: Age is a minor determinant of mammographic sensitivity in women aged 40 years or older. Sensitivity is substantially decreased with the combination of higher breast density and estrogen replacement therapy use. There was not a notable shift in cancer outcomes in the groups with lower mammographic sensitivity. These data do not support different screening recommendations in women aged 40-49 years or in estrogen replacement therapy users.     

Prospective, randomized trial of prolonged intracoronary urokinase infusion for chronic total occlusions in native coronary arteries

OBJECTIVES: The purpose of this study was to determine the safety and efficacy of three dosing regimens of intracoronary urokinase for facilitated angioplasty of chronic total native coronary artery occlusions. BACKGROUND: Percutaneous transluminal coronary angioplasty of chronically occluded (>3 months) native coronary arteries is associated with low initial success secondary to an inability to pass the guide wire beyond the occlusion. METHODS: Patients were enrolled if a chronic total occlusion >3 months old could not be crossed with standard angioplasty equipment. Of the 101 patients enrolled, 41 had successful guide wire passage and were excluded from urokinase treatment. The remaining 60 patients were randomized to receive one of three intracoronary dosing regimens of urokinase over 8 h (group A = 0.8 million U; group B = 1.6 million U; group C = 3.2 million U), and angioplasty was again attempted after completion of the urokinase infusion in 58 patients. RESULTS: Coronary angioplasty was successful in 32 patients (53%) (group A 52%, group B 50%, group C 59%, p = 0.86). This study had a 90% power to detect at least a 50% difference between dosing groups at alpha 0.05. Bleeding complications requiring blood transfusion did not differ significantly among the dosing groups (A 0%, B 15%, C 6%, p = 0.14), although major bleeding episodes were less common in group A (p < 0.05). There were no major procedural or in-hospital complications. Angiographic follow-up in 69% of the patients with successful angioplasty revealed target vessel patency in 91% but an angiographic restenosis rate of 59%. CONCLUSIONS: A prolonged supraselective intracoronary infusion of urokinase can be safely administered and may facilitate angioplasty of chronic total occlusions. Lower doses of urokinase are equally effective and result in fewer bleeding complications than do higher dosage regimens. Vessel patency is frequently maintained, but restenosis remains a problem.