Biophotonic Tools in Cell and Tissue Diagnostics.

In order to maintain the rapid advance of biophotonics in the U.S. and enhance our competitiveness worldwide, key measurement tools must be in place. As part of a wide-reaching effort to improve the U.S. technology base, the National Institute of Standards and Technology sponsored a workshop titled "Biophotonic tools for cell and tissue diagnostics." The workshop focused on diagnostic techniques involving the interaction between biological systems and photons. Through invited presentations by industry representatives and panel discussion, near- and far-term measurement needs were evaluated. As a result of this workshop, this document has been prepared on the measurement tools needed for biophotonic cell and tissue diagnostics. This will become a part of the larger measurement road-mapping effort to be presented to the Nation as an assessment of the U.S. Measurement System. The information will be used to highlight measurement needs to the community and to facilitate solutions.

Long axis electromechanics during dobutamine stress in patients with coronary artery disease and left ventricular dysfunction.

OBJECTIVE: To dissociate the effect of inotropy from activation change during dobutamine stress on left ventricular long axis function in patients with coronary artery disease (CAD). METHODS: 25 patients with CAD and normal left ventricular cavity size and 30 with cavity dilatation-18 with normal activation (DCM-NA) and 12 with left bundle branch block (DCM-LBBB)-were compared with 20 controls. 12 lead ECG and septal long axis echograms were assessed at rest and peak dobutamine stress. Amplitude, shortening and lengthening velocities, postejection shortening, Q wave to onset of shortening (Q-OS), and A2 to onset of lengthening (A2-OL) were measured. Inotropy was evaluated from peak aortic acceleration. RESULTS: In controls, amplitude, shortening and lengthening velocities, and peak aortic acceleration increased with stress; QRS, Q-OS, and A2-OL shortened (all p < 0.001); and contraction remained coordinate. In the group of patients with CAD and normal left ventricular cavity size, shortening velocity and peak aortic acceleration increased with stress (p < 0.005). However, amplitude and lengthening velocity did not change, QRS, Q-OS, and A2-OL lengthened (p < 0.01), and incoordination appeared. Results were similar in the group with DCM-NA. In the DCM-LBBB group, shortening velocity and peak aortic acceleration increased modestly with stress (p < 0.01) but amplitude, lengthening velocity, QRS, Q-OS, A2-OL, and incoordination remained unchanged. Overall, change in shortening velocity correlated with that in peak aortic acceleration (r(2) = 0.71), in amplitude with that in lengthening velocity (r(2) = 0.74), and in QRS with both Q-OS (r(2) = 0.69) and A2-OL (r(2) = 0.63). CONCLUSION: The normal long axis response to dobutamine reflects both inotropy and rapid activation. In CAD, inotropy is preserved with development of ischaemia but the normal increase in amplitude is lost and prolonged activation delays the time course of shortening, causing pronounced incoordination. Overall, shortening rate uniformly reflects inotropy while lengthening rate depends mainly on systolic amplitude rather than primary diastolic involvement, even with overt ischaemia.

Incidence, location, pathology, and significance of pulmonary homograft stenosis after the Ross operation.

BACKGROUND: The Ross operation has several theoretical advantages. However, concern exists regarding evolving pathology in the pulmonary homograft. METHODS AND RESULTS: Consecutive patients (n=144; mean age 31 years, range 2 months to 64 years) undergoing the Ross operation were studied between 1993 and 2000. Echocardiographic examination of the pulmonary homograft was performed immediately after surgery, then at yearly intervals for a mean interval of 48 months. Fifteen patients (mean age 37 years) in whom echocardiography revealed peak pulmonary gradients >/=30 mm Hg (mean 46+/-18 mm Hg) underwent MRI with velocity mapping in a Picker 1.5-T magnet. No patient had more than mild pulmonary regurgitation. Four patients required reoperation for rapidly progressive pulmonary homograft stenosis; in all 4, there was macroscopic and microscopic evidence of a pronounced chronic adventitial reaction, with perivascular infiltration producing extrinsic compression. Freedom from any pulmonary homograft stenosis at 7-year follow-up was 79.7%, with instantaneous hazard falling to zero after 4 years. Freedom from reoperation at 7 years was 96.7%. In those studied with MRI, there was evidence of narrowing of the whole homograft or distal suture line in 14 of 15 patients, with obvious excess surrounding tissue in 11. Mean minimum diameter and peak velocity by MRI were 11+/-2 mm and 3.2+/-0.7 m/s, respectively. Multivariate analysis of patient-, surgery-, and homograft-related variables did not reveal any significant risk factors for development of neopulmonary stenosis. CONCLUSIONS: Pulmonary homograft stenosis after the Ross operation is clinically important and appears to represent an early postoperative inflammatory reaction to the pulmonary homograft that leads to extrinsic compression and/or shrinkage.

Mitral annulus dynamics: determinants of left ventricular filling.

OBJECTIVES: To examine the influence of mitral annular dynamics on left ventricular filling. METHODS: Twenty patients (mean age 64 +/- 6 years) with coronary artery disease and normal left ventricular function were studied by transesophageal echocardiography immediately before bypass grafting with the pericardium open. Pulmonary venous and transmitral velocities were recorded with pulsed wave Doppler. Mitral annulus position was derived by M-mode and its rate of change by digitisation of the records. From simultaneous high fidelity left atrial pressure, instantaneous power and its time integral work were derived. RESULTS: In all patients the power curve was triphasic, being positive in both early and late diastole and negative during ventricular systole. Systolic annular work was related to pulmonary venous peak systolic velocities (r = 0.74, p < 0.001). The ratio of the early to late diastolic annular work correlated with the transmitral E/A ratio (r = 0.82, p < 0.0001) and early diastolic work was related to pulmonary venous peak diastolic velocities (r = 0.74, p < 0.001). Pressure-displacement curves of the annulus throughout the period of rapid ventricular filling were curvilinear with instantaneous stiffness increasing with distension. In addition all curves demonstrated a diastolic equilibrium point of zero stiffness. CONCLUSIONS: Mitral annulus function, particularly when work and power are calculated, appear to be an important determinant of left ventricular filling. The underlying mechanics may also explain the variations in transmitral and pulmonary venous Doppler patterns seen in diseased states.

Aortic root characteristics of human pulmonary autografts.

BACKGROUND: After pulmonary autograft replacement of the aortic valve and root, the pulmonary artery (PA) wall is subjected to higher pressures. Concern exists that this may lead to structural and functional changes in the implanted autograft and subsequent aortic root dilatation and neoaortic regurgitation. We therefore assessed root dimensions and neoaortic regurgitation, morphological structure, and mechanical behavior in patients who underwent the Ross operation. METHODS AND RESULTS: Seventy-four patients who were randomized to undergo aortic valve replacement with an aortic homograft or a pulmonary autograft were followed up echocardiographically for up to 4 years and had their aortic root dimensions measured at the level of the annulus, sinuses, and sinotubular junction. In a separate series of 18 patients who underwent pulmonary autograft surgery and 8 normal organ donors, samples from the PA and aorta were analyzed for medial wall thickness, distribution of the staining of collagen and elastin, and elastin fragmentation. Finally, stress-strain curves were obtained from samples of the PA and aorta from 9 patients who underwent pulmonary autograft surgery and from 1 patient in whom a 4-month-old autograft was explanted. No patient in either group had aortic dilatation at any level of >20% or more than mild aortic regurgitation at up to 4 years of follow-up. The aortic media was thicker in both autografts and normal donors (P:<0.01), and there was a trend for the PA media to be thicker in the autograft group. Elastic fiber in all aortas showed little or no variation, whereas in the PA, there was considerable variation in fragmentation. Patients with higher preoperative PA pressures tended to have lower fragmentation scores (chi(2) P:<0.01). The lower stiffness modulus, higher stiffness modulus, and maximum tensile strength of the aorta was 34% to 38% higher than that of the PA (P:<0.01); however, the 4-month-old autograft appeared to show adaptation in mechanical behavior. CONCLUSIONS: In our series of patients, there was no significant progressive dilatation of the aortic root. We demonstrated differences in the anatomic structure and mechanical behavior of the PA in vitro and highlighted histological and mechanical modes of adaptation.

Pulmonary autograft versus aortic homograft for aortic valve replacement: interim results from a prospective randomized trial.

BACKGROUND AND AIM OF THE STUDY: Although pulmonary autografts offer advantages over aortic homografts, they may also carry additional risks. We reviewed the interim results of a prospective randomized trial of autograft versus homograft aortic valve replacement (AVR) to determine if the greater complexity of the autograft insertion is justified, particularly with regard to time-related hemodynamic function. METHODS: A total of 182 patients (82% male, 18% female; mean age 37.2 +/- 14.3 years; range: 2-64 years) with isolated aortic valve disease were randomized to pulmonary autograft (group A, n = 97) or aortic homograft (group H, n = 85); 42% had previous aortic valve surgery and 19% had native or prosthetic valve endocarditis. Follow up included annual outpatient visits and echocardiography. RESULTS: Autograft AVR required longer cross-clamp (41%) and bypass (43%) times, but did not result in significantly more bleeding, longer recovery or more complications. One 30-day death occurred in group A (1%), and three deaths in group H (4%). Median follow up was 33.9 months (range: 1-61 months). There was one late death in each group, three reoperations in group A (all for pulmonary homografts), and three in group H (including two aortic homograft reoperations, both in children). There were no autograft reoperations. There were no other valve-related events. At 48 months, actuarial survival and reoperation-free survival rates were 97.8% and 94.2% in group A, and 95.3% and 87.7% in group H (p = NS). Echocardiography showed near-perfect function in all autografts, but early signs of subclinical dysfunction in many homografts. CONCLUSION: Both autograft and homograft AVR are safe and produce good intermediate-term results. Early homograft degeneration appears to favor autografts in children. The echocardiographic findings may translate into superior long-term autograft durability and hemodynamics.

Right ventricular function after pulmonary autograft replacement of the aortic valve.

BACKGROUND: The pulmonary autograft operation (the Ross procedure) involves excision of a portion of the right ventricular (RV) outflow tract, prolonged cross-clamp times, and insertion of a pulmonary homograft. There is concern about the effect of such operations on right ventricular function. METHODS AND RESULTS: Twenty-five patients undergoing either pulmonary autograft or homograft replacement of the aortic valve as part of a prospective randomized trial had echocardiographic RV long-axis measurements performed before surgery and 6 months (range 3 to 12 months) after surgery. In all patients, systolic excursion (SE) and both shortening and lengthening rates (SR and LR, respectively) were reduced postoperatively (P<0.05) (homografts: SE 1.5+/-0.4 versus 2.3+/-0.6 cm, SR 6.8+/-2.1 versus 9. 6+/-3.1 cm/s, LR 6.0+/-1.8 versus 8.9+/-3.0 cm/s; autografts: SE 1. 4+/-0.4 versus 2.2+/-0.4 cm, SR 5.8+/-3.0 versus 8.2+/-3.0 cm/s, LR 5.7+/-1.9 versus 8.5+/-3.7 cm/s). There were no differences between the 2 groups. Eighteen patients who had undergone either aortic homograft or pulmonary autograft surgery were studied between 6 and 35 months after surgery. RV volumes were assessed with the use of MRI in addition to echocardiographic RV long-axis measurements. Global volumes were increased to a similar amount in both groups (homografts: end-diastolic volume 145+/-34 mL, end-systolic volume 78+/-23 mL; autografts: end-diastolic volume 157+/-33 mL, end-systolic volume 89+/-25 mL; P=NS), whereas stroke volumes were maintained in both groups (homografts 67+/-15 mL, autografts 67+/-16 mL; P=NS). RV SE was depressed in both groups to a similar degree to that seen with the previous group (homografts 1.5+/-0.3 cm, autografts 1.4+/-0.2 cm). CONCLUSIONS: Aortic valve replacement with either a pulmonary autograft or an aortic homograft leads to a degree of persistent RV longitudinal dysfunction that is not more pronounced in those undergoing the Ross procedure. The mechanisms and long-term effects of these changes must be further studied.

Pulmonary autograft versus aortic homograft for rereplacement of the aortic valve: results from a subset of a prospective randomized trial.

BACKGROUND: The use of a pulmonary autograft for rereplacement of the aortic valve has both potential advantages and disadvantages. This study details the early results of a subset of patients enrolled in a prospective randomized trial comparing pulmonary autografts and aortic homografts who have had previous aortic valve replacements. METHODS AND RESULTS: A total of 47 patients who had undergone >/=1 previous aortic valve replacement were randomized to receive either a pulmonary autograft (24 patients aged 40+/-11 years) or an aortic homograft (23 patients aged 37+/-11 years) for rereplacement of the aortic valve. One early death occurred in the homograft group, and 1 late (7 months) death occurred in the autograft group. One patient who received a pulmonary autograft was reoperated on for inflammatory pulmonary stenosis. One patient in each group was reopened for bleeding (both within 24 hours). Two patients in the autograft group had postoperative neurological weakness; they fully recovered over 2 months. Hospital stay, blood loss, incidence of perioperative arrhythmia, and markers of coronary ischemia were similar between the 2 groups. At 6-month follow-up (range, 1 to 12 months), left ventricular end-diastolic diameter was similar in both groups (homografts, 5.0+/-0.9 cm; autografts, 5.2+/-0.6 cm; P=NS), and no patient in either group had significant aortic valve dysfunction. CONCLUSIONS: Rereplacement of the aortic valve with a pulmonary autograft is feasible and safe in patients aged 14 to 60, regardless of their preoperative diagnosis or clinical condition.

Intraoperative cardiac troponin T release and lactate metabolism during coronary artery surgery: comparison of beating heart with conventional coronary artery surgery with cardiopulmonary bypass.

OBJECTIVE: To compare cardiac troponin T release and lactate metabolism in coronary sinus and arterial blood during uncomplicated coronary grafting on the beating heart with conventional coronary grafting using cardiopulmonary bypass. DESIGN: A prospective observational study with simultaneous sampling of coronary sinus and arterial blood: before and 1, 4, 10, and 20 minutes after reperfusion for analysis of cardiac troponin T and lactate. Cardiac troponin T was also analysed in venous samples taken 3, 6, 24, 48, and 72 hours after surgery. SETTING: Cardiac surgical unit in a tertiary referral centre. PATIENTS: 18 patients undergoing coronary grafting on the beating heart (10 single vessel and eight two-vessel grafting) and eight undergoing two-vessel grafting with cardiopulmonary bypass. RESULTS: Cardiac troponin T was detected in coronary sinus blood in all patients by 20 minutes after beating heart coronary artery surgery before arterial concentrations were consistently increased. Peak arterial and coronary sinus cardiac troponin T values on the beating heart during single (0.03 (0 to 0. 05) and 0.09 (0.07 to 0.16 microg/l, respectively) and two-vessel grafting (0.1 (0.07 to 0.11) and 0.19 (0.14 to 0.25) microg/l) were lower than the values obtained during cardiopulmonary bypass (0.64 (0.52 to 0.72) and 1.4 (0.9 to 2.0) microg/l) (p < 0.05). The area under the curve of venous cardiac troponin T over 72 hours for two-vessel grafting on the beating heart was less than with cardiopulmonary bypass (13 (10 to 16) v 68 (26 to 102) microg.h/l) (p < 0.001). Lactate extraction began within one minute of snare release during beating heart coronary surgery while lactate was still being produced 20 minutes after cross clamp release following cardiopulmonary bypass. CONCLUSIONS: Lower intraoperative and serial venous cardiac troponin T concentrations suggest a lesser degree of myocyte injury during beating heart coronary artery surgery than during cardiopulmonary bypass. Oxidative metabolism also recovers more rapidly with beating heart coronary artery surgery than with conventional coronary grafting. Coronary sinus cardiac troponin T concentrations increased earlier and were greater than arterial concentrations during beating heart surgery, suggesting that this may be a more sensitive method of intraoperative assessment of myocardial injury.

Effect of coronary occlusion on left ventricular function with and without collateral supply during beating heart coronary artery surgery.

OBJECTIVE: To study the effects of coronary occlusion and collateral supply on left ventricular (LV) function during beating heart coronary artery surgery. DESIGN: Prospective intraoperative study, performed at baseline, during wall stabilisation, coronary artery occlusion, and 2 and 10 minutes after reperfusion. Transoesophageal M mode echocardiograms, simultaneous high fidelity LV pressure, and thermodilution cardiac output were measured. LV anterior wall thickening, thinning velocities, thickening fraction, regional work, and power production were derived. Asynchrony during the isovolumic periods was quantified as cycle efficiency. SETTING: Tertiary referral cardiac centre. PATIENTS: 14 patients with stable angina, mean (SD) age 62 (7) years, undergoing left anterior descending artery grafting using the "Octopus" device. RESULTS: Collaterals were absent in nine patients and present in five. Epicardial stabilisation did not affect LV function. Results are expressed as mean (SD). Coronary occlusion (15.6 (2) minutes) depressed anterior wall thickening (1.4 (0.6) v 2.6 (0.6) cm/s) and thinning velocities (1.4 (0.5) v 3.0 (0.6) cm/s), regional work (2.2 (0.8) v 4.6 (0.6) mJ/cm2), and power (21 (4) v 33 (5) mW/cm2) in patients without collaterals (p < 0.05 for all), but only wall thinning (3.5 (0.5) v 4.8 (0.5) cm/s, p < 0.05) in patients with collaterals. All returned to baseline within 10 minutes of reperfusion. Cycle efficiency and regional work were impaired at baseline and fell during occlusion, regardless of collaterals. Within 10 minutes of reperfusion both had increased above baseline. CONCLUSIONS: Coronary occlusion for up to 15 minutes during beating heart coronary artery surgery depressed standard measurements of systolic and diastolic anterior wall function in patients without collaterals, but only those of diastolic function in patients with collaterals. Regional synchrony decreased in both groups. All disturbances regressed within 10 minutes of reperfusion.

A technique to create appropriate abutment tooth contours for removable partial dentures.

A technique is presented for using light-cured composite resin to create desirable contours on abutment teeth for the retention and support of removable partial dentures. The desired tooth shape is created on a diagnostic cast, captured in a clear temporary splint material, and formed in resin on the abutment teeth with the splint acting as a matrix.

Scattering from a V-shaped groove in the resonance domain.

Radiation scattered from a V-shaped groove in the resonance domain was measured and compared to predictions from a rigorous theory. The calculated scattering accurately predicted the number of peaks and general shape of the observed scattering. Small variations in groove shape were found to alter peak heights noticeably and peak positions slightly. Finite beam size caused unavoidable discrepancies between calculated and measured scattering.

In vitro effects of prednisolone sodium succinate and Escherichia coli organisms on neutrophil survival, glucose utilization, and E coli clearance in canine blood.

A concentration of 1.4 X 10(9) Escherichia coli was added to tubes containing 10 ml of freshly collected blood from dogs to determine if prednisolone sodium succinate altered in vitro E coli mortality, glucose utilization, or neutrophil destruction. Group 1 tubes contained organisms plus saline solution, group 2 tubes had E coli plus 140 microgram of prednisolone/ml, and group 3 tubes contained E coli plus 1,400 microgram of prednisolone/ml. Initial and final WBC, RBC, PCV and E coli concentrations were determined on each group. Blood glucose values were measured from zero time through +2 hours. There was a significant (P less than 0.001) reduction in the number of E coli in vitro for all groups, but there was no difference among the groups. Fewer neutrophils (P less than 0.01) were lost in the tubes containing either concentration of prednisolone than in the tubes containing E coli alone. At the therapeutic amount of prednisolone (group 2) the glucose utilization was not significantly (P greater than 0.05) different from the utilization in the control group; however, at 10 X the therapeutic amount of prednisolone (group 3), there was an increase in glucose utilization. Seemingly, prednisolone does not alter in vitro E coli destruction and aids in preserving neutrophils of canine blood.

Diffraction from a shallow rectangular groove.

Infrared radiation scattered from a shallow groove is found to exhibit the same diffraction pattern as a single slit. A model based on a beam with a Gaussian intensity profile was found which explains the observed scattering patterns and which also describes the scattering pattern occurring when certain alignment errors are present in the system. The large scattering intensity from the shallow (depth ~lambda/20) groove has implications in the use of optical scattering as a tool for nondestructive evaluation of surface flaws.

Past and current trends in negligence and incompetence arbitration.

With the inclusion of the phrase "just cause" in the collective-bargaining agreement, management found itself bound by new and complex limitations concerning discharge for negligence/incompetence. In this study, the author examines a variety of discharge cases, as well as the changing (and intelligent) management attitudes they represent.

Rosette formation by canine peripheral blood lymphocytes.

The surface membrane characteristics of canine peripheral blood lymphocytes were investigated using erythrocyte (E) and erythrocyte antibody complement (EAC) rosette assays and immunofluorescent staining techniques. Canine thymus-derived lymphocytes formed nonimmune E rosettes with human and guinea pig erythrocytes at approximately the same percentages (mean percentage 36.3 and 32.4, respectively). Rosettes did not form with erythrocytes from seven other animal species. Cell surface immunoglobulins were demonstrable in a small percentage (4%) of the E rosette-forming lymphocyte population. Fragments of human erythrocytes inhibited E rosette formation by intact human red cells, but did not result in a significant decrease in rosette formation by intact guinea pig erythrocytes; likewise, guinea pig fragments had no inhibitory effect on rosette formation by human erythrocytes, demonstrating that separate receptors were required for the two red cell types. EAC rosette formation was not affected by addition of intact or fragmented human and guinea pig erythrocytes. Canine bone marrow-derived lymphocytes were characterized by immunoglobulin on the cell surface and EAC rosette formation. Serial tests of lymphocytes from one dog revealed a wide variation in percentage of cells forming E and EAC rosettes. A close correlation was observed between the immunoglobulin-bearing cells (mean percentage 46.6) and those forming EAC rosettes (mean percentage 49.3).